90+ Facts That Will Make You Want to Become a Body Hacker

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Transcript

00:00:00 Now, if you don't want to sneeze, press the skin on the bridge of your nose with your

00:00:05 fingers.

00:00:06 When you do it, your brain receives an alarm signal.

00:00:09 Very quickly, it puts the brakes on all other processes, including the sneezing reflex.

00:00:15 By the way, the longest sneezing fit was recorded in 1981.

00:00:21 It lasted for 976 days!

00:00:25 During this time, a woman from the UK sneezed more than a million times!

00:00:30 The part of your brain that's responsible for vision is in the back of your head.

00:00:35 Interestingly, the right side of your brain controls the vision on the left side and vice

00:00:40 versa.

00:00:42 If you're in some loud place, for example, in a club or at a concert, close your ears

00:00:47 to better hear your friends.

00:00:50 Push the tragus, the pointed skin-covered cartilage in front of the ear canal, into

00:00:54 your ear.

00:00:55 Then, turn this ear toward your friend.

00:00:59 If you feel anxious, press your fingers into a fist with your thumb sticking out and slowly

00:01:04 blow on this finger.

00:01:07 If you can't stop hiccups, put an ice cube on your tongue.

00:01:11 Or you can close your ears with your palms and drink a glass of water through a straw

00:01:15 in one breath.

00:01:18 Pulling the tip of your tongue or raising your arms toward the ceiling can also be helpful.

00:01:24 On average, when a person snores, the sound doesn't get louder than 60 decibels.

00:01:29 That's as loud as a regular conversation.

00:01:32 But sometimes the noise levels can reach 80 decibels.

00:01:36 That's as loud as a working food blender.

00:01:40 If you want to wake up faster, hold your breath for some time.

00:01:43 When you do it, your heart starts beating more rapidly, and your body turns on the active

00:01:48 mode.

00:01:49 But don't overdo it!

00:01:50 If you wake up too abruptly, you'll put unnecessary stress on your heart.

00:01:55 If you feel moody, hold a pencil between your teeth.

00:01:59 The muscles involved in smiling will get down to work.

00:02:02 This will send special impulses to your brain, and it'll start producing endorphins.

00:02:07 In no time, your smile will become much more sincere.

00:02:13 Left-handed people tend to chew most of their food on the right side of their mouths, and

00:02:17 those who are left-handed use their left side more.

00:02:21 The smell of rosemary can help you activate your super memory.

00:02:25 Whenever you need to learn something by heart, do it while lying down in bed with a sprig

00:02:30 of rosemary nearby.

00:02:32 It'll help you memorize the info more effectively and faster.

00:02:37 If your leg has fallen asleep, shake your head.

00:02:40 In about a minute, you'll realize that your muscles have relaxed, and the pins and needles

00:02:45 sensation has passed.

00:02:48 The muscles that help your eyes focus make around 100,000 movements a day.

00:02:54 If you want to make your leg muscles move as much, you'll need to walk 50 miles.

00:03:00 Déjà vu might actually be something like a brain processing lag.

00:03:03 There's a theory claiming it might happen when your brain is moving information from

00:03:08 one part to another.

00:03:10 If there's even the tiniest delay in that process, your brain will get the same information

00:03:14 twice.

00:03:15 In this case, it'll process it as an event that happened before.

00:03:21 Out of all those people who can move their ears, only 30% can move just one ear.

00:03:27 Your mouth burns when you're snacking on pineapple because while you're eating this

00:03:31 fruit, it's eating you back.

00:03:34 Pineapple is the only known food that contains bromelain.

00:03:38 It's an enzyme that breaks down proteins.

00:03:40 Luckily, your stomach acid knows how to deal with the offending enzyme.

00:03:46 If you have a tickle in your throat, scratch your ear.

00:03:49 This stimulates a nerve, which results in a muscle spasm in your throat.

00:03:53 And in no time, the tickle is gone.

00:03:56 Surprisingly, you burn more calories when you're sleeping than when you're watching

00:04:01 TV.

00:04:02 Ask your friend to sit down on a chair and put your index finger on their forehead.

00:04:07 And tell them to stand up without using their hands.

00:04:11 They won't be able to do it.

00:04:14 Just like salamanders regrow their tails, humans might be able to regenerate cartilage.

00:04:19 That's rubber-like stuff surrounding your joints.

00:04:22 Scientists have recently discovered that cartilage could repair itself.

00:04:26 This process is likely to be the most effective at the ankle, not that effective in the knee,

00:04:32 and the least effective in the hip.

00:04:36 If you're lying in bed and suddenly experience vertigo, place one of your feet on the floor.

00:04:42 Your brain will receive the information that you're standing on something firm, and the

00:04:46 unpleasant sensation will pass.

00:04:50 Only 30% of people can flare their nostrils.

00:04:54 If someone is tapping you on the back while you're hugging, they're non-verbally asking

00:04:58 you to let go.

00:05:00 People with a single palmar crease have just one line running across their palm.

00:05:06 Such people are very rare – just 1.5% of the world's population.

00:05:11 Most people have two palmar creases.

00:05:13 Men are more likely to have a single palmar crease than women.

00:05:17 In most cases, it runs in families.

00:05:20 Your taste buds have a very short life cycle.

00:05:23 They live for no longer than 10-14 days.

00:05:28 Your lips are hundreds of times more sensitive than your fingertips.

00:05:33 Your skin wrinkles when you stay in the water for too long.

00:05:36 But it doesn't happen because it absorbs water.

00:05:39 In reality, wrinkled fingers and toes provide you with a better grip.

00:05:44 Studies have proved that sneezing is your nose's way to reset.

00:05:48 A sneeze reboots the cells that line the insides of your nose.

00:05:53 They're called cilia.

00:05:55 If a person has anosmia, which is also called smell blindness, they don't distinguish

00:06:01 and detect smells.

00:06:04 The amount of food you consume in your lifetime will weigh as much as 8 Asian elephants.

00:06:09 No wonder that people spend almost 4 years of their life eating!

00:06:14 Your skin analyzes 1 million bits of data per second.

00:06:18 Your ears and nose process 100,000 bits each.

00:06:22 And your tongue is the least productive.

00:06:24 It analyzes just 1,000 bits.

00:06:29 Multitasking is kind of impossible.

00:06:32 What we consider multitasking is actually just our brain switching between different

00:06:36 tasks really fast.

00:06:38 Unfortunately, in this case, people tend to make mistakes much more often.

00:06:42 Plus, you may need twice as much time to do a task as usual.

00:06:48 On the other hand, when you're engaged in some physical activity you've done many

00:06:51 times before, you can perform a mental task too.

00:06:55 That's why you can easily jog or take a shower and think about problems at work.

00:07:01 If you see someone constantly fixing their sleeves, they likely feel very nervous, and

00:07:07 fiddling with something is a self-soothing technique.

00:07:11 You can check how unique you are by chewing on a sprig of cilantro.

00:07:16 For some people, this herb may taste similar to soap because the plant contains a chemical

00:07:20 used in soap making.

00:07:22 But only 4-14% of the world's population have special genes that can detect it.

00:07:28 Are you one of them?

00:07:31 A grown-up person uses around 200 muscles to make just one step.

00:07:37 Your eyes never stop moving while taking in visual information.

00:07:41 Otherwise, you wouldn't be able to see the whole picture.

00:07:44 These movements go unnoticed because your brain is a great video editor.

00:07:49 It stabilizes the images and connects tons of fragments into one smooth video.

00:07:55 Your stomach gets a totally new lining every 3-4 days.

00:07:59 That's how your body prevents the stomach from digesting itself.

00:08:04 When a person lies, the temperature around their nose and in the inner corners of their

00:08:09 eyes rises.

00:08:11 This phenomenon is known as the Pinocchio effect.

00:08:16 The liver is the only human organ that can regenerate completely.

00:08:21 Even if it's a mere 25% of the original liver weight, the organ can get back to its

00:08:26 full size.

00:08:28 Synepsia is an unusual and rare ability.

00:08:32 People who have it can taste music or hear colors.

00:08:35 But only 1 in every 2,000 people has it.

00:08:39 These days, our finger and toenails grow faster than they did half a century ago.

00:08:45 It might be because people eat more proteins today.

00:08:50 You start feeling thirsty once your water loss reaches 1% of your body weight.

00:08:55 More than 5%, and you may even faint.

00:08:59 Water loss that exceeds 10% of the body weight, um, we'll just say that it doesn't end

00:09:04 well.

00:09:08 Your brain can generate more than 48 thoughts in under a minute.

00:09:12 That's almost 3,000 thoughts per hour and more than 70,000 per day!

00:09:19 Each person has around 150,000 hairs on their head.

00:09:23 On average, every strand grows about a half an inch per month.

00:09:26 If you combine the growth from each hair, it would measure the distance of 10 miles

00:09:31 per year.

00:09:33 If you get a leg cramp, pull your big toe toward yourself.

00:09:37 This will stretch your muscles and reduce the spasm.

00:09:42 People have bacteria that can produce electricity living in their intestines.

00:09:46 These bacteria give off electrons, which creates tiny electrical currents.

00:09:51 This might be the bacteria's way to generate energy.

00:09:54 Maybe turn on some lights.

00:09:56 Hey, it's dark in there!

00:09:58 By the end of their life, the average person can recall up to 150 trillion pieces of information.

00:10:06 If you brush your teeth before eating or drinking something, you might end up damaging your

00:10:11 taste buds.

00:10:12 That's because most kinds of toothpaste contain two chemicals, sodium lauryl ether

00:10:17 sulfate and sodium lauryl sulfate, that decrease your ability to taste sweet things and increase

00:10:23 your ability to taste bitter food.

00:10:27 The DEC2 gene mutation allows people to have just a few hours of sleep a night and still

00:10:33 feel great.

00:10:35 They don't get tired and never sleep in.

00:10:37 Boy, where do I get one of those!

00:10:40 On average, these people wake up at 4 or 5 am.

00:10:43 Only up to 5% of the world's population has this feature.

00:10:48 Only humans can produce emotional tears.

00:10:51 Other living beings cry to lubricate their eyes.

00:10:56 Women have more taste buds on their tongues than men do.

00:11:00 It might be one of the reasons why 35% of ladies are supertasters – people who feel

00:11:06 flavors more strongly than others.

00:11:09 And only 15% of guys can boast the same ability.

00:11:13 It's hard for people to recognize someone they know if, in a photo, this person doesn't

00:11:19 have eyebrows.

00:11:21 This proves that eyebrows are more important for face recognition than eyes.

00:11:27 When clasping their hands, 50% of people put their right thumb above the left one.

00:11:32 49% of people position their left thumb over the right.

00:11:37 And only 1% of people place their thumbs next to each other.

00:11:43 Your brain contains more than 86 billion nerve cells, which are joined with one another by

00:11:48 100 trillion connections.

00:11:50 That's way more than the number of stars in our home Milky Way galaxy.

00:11:55 And if you decided to count all those numerous nerve cells, it would take you up to 3,000

00:12:01 years.

00:12:02 A tremendous waste of time.

00:12:06 Your brain's memory capacity equals 4 terabytes on a hard drive.

00:12:10 That's more than 8 million photos.

00:12:13 You're likely to keep in memory up to 10,000 different faces.

00:12:18 This number is different from person to person, but the average is 5,000.

00:12:22 It doesn't mean you can put a name to each face.

00:12:25 It's only about recognizing the features.

00:12:29 If you walked in the same direction for 12 hours a day, you would need around 800 days

00:12:34 to travel around the globe.

00:12:37 The Bajau is a group of nomadic people that live in the waters surrounding the Philippines,

00:12:42 Indonesia, and Malaysia.

00:12:44 Thanks to a rare DNA mutation, they can stay underwater for up to 13 minutes.

00:12:50 They also dive to a depth of 200 feet.

00:12:54 Blue cheese can affect your dreams, making them more vivid.

00:12:59 Your ears might pop or even hurt when you were on an airplane.

00:13:03 You can solve this problem by simply chewing some gum.

00:13:07 This opens up the eustachian tube, a small passage that connects your throat and your

00:13:11 middle ear.

00:13:13 Opening this passage up helps equalize the pressure in your ears and puts an end to the

00:13:17 popping.

00:13:18 You can also yawn to open up the eustachian tube.

00:13:23 Your dreams are a complex mix of your imagination, memories, and knowledge.

00:13:28 The average person has from 4 to 7 dreams every night.

00:13:32 But not all people remember them.

00:13:35 Even if fingerprints get badly damaged, they grow back with their original pattern.

00:13:41 If you have to deal with complaining customers, put a mirror behind your back.

00:13:45 When an angry person approaches you, they'll see themselves in the mirror.

00:13:49 This will prevent them from acting rudely.

00:13:52 No one likes seeing themselves this way.

00:13:56 Your feet are likely to become bigger with time.

00:13:58 When people grow older, ligaments and tendons in their feet weaken.

00:14:02 This makes the arches flatter, and feet become wider and longer.

00:14:08 Only 3% of people in the world have lines that form the letters "X" on both their

00:14:14 palms.

00:14:15 In many cultures, this is believed to be a sign of a strong personality.

00:14:20 The human brain is 73% water, just like your heart.

00:14:24 That's why if your brain loses even 2% of liquid, you start feeling exhausted.

00:14:30 This also makes your memory worse, shortens your attention span, and puts a dampener on

00:14:34 your mood.

00:14:37 In most people, their height is the same as their arm span.

00:14:41 Check it out!

00:14:43 A particular gene mutation results in super dense bones that are almost impossible to

00:14:48 break.

00:14:49 They're several times tougher than the average person's bones.

00:14:52 People with this mutation also have skin that is less prone to aging.

00:14:58 You might have noticed little dots traveling in squiggly lines when you're looking at

00:15:02 a bright light or blue sky.

00:15:04 They're usually only visible for a second or two.

00:15:08 Sometimes they look like tiny worms.

00:15:10 Well, those are your white blood cells moving through the capillaries in front of the retina.

00:15:15 The light-sensitive tissue at the back of your eyes.

00:15:19 Most people don't even notice the dots unless you ask them to pay attention.

00:15:25 If someone is listening to you with their eyebrows raised, they're likely genuinely

00:15:29 interested in your story.

00:15:32 If you decided to uncoil the human DNA, the whole thing would stretch for 10 billion miles.

00:15:39 That's 40,000 times the distance between Earth and the Moon.

00:15:44 Human teeth are almost as strong as those of a shark.

00:15:48 The enamel of your teeth, that's the outer layer, is the hardest substance in your entire

00:15:53 body.

00:15:55 Your nostrils don't work with the same efficiency all the time.

00:15:59 When you breathe, one nostril does most of the work.

00:16:02 They switch every couple of hours.

00:16:05 Your right ear is more responsive to speech, and your left ear is better at perceiving

00:16:10 music.

00:16:11 Researchers think that's because it's your left hemisphere that processes speech, while

00:16:15 the right one deals with music and other creative functions.

00:16:20 Your lips look red because of a great number of tiny blood capillaries right below the

00:16:25 skin.

00:16:27 While enjoying your favorite cold food or beverage, you might suddenly get a painful

00:16:31 brain freeze.

00:16:33 This happens because the nerves at the roof of your mouth get frozen.

00:16:37 They send signals to your brain asking it to please stop eating such cold stuff.

00:16:42 But you can overcome this unpleasant sensation by pressing your tongue against the roof of

00:16:47 your mouth.

00:16:48 Do it as hard as you can – the pain will soon disappear.

00:16:54 Your lips don't sweat because there are no sweat glands there.

00:16:57 They also have no glands producing a special protective film that keeps your skin hydrated.

00:17:02 That's why your lips are so vulnerable to the sun, wind, and cold.

00:17:07 They also dry out faster than other body parts.

00:17:11 You wouldn't be able to taste food if your body didn't produce saliva.

00:17:15 Your taste buds have special receptors that recognize different flavors.

00:17:19 But without some liquid, flavors won't bind to the molecules of these receptors.

00:17:25 There are only a few cells in your body that will stay with you throughout your entire

00:17:29 life.

00:17:30 Those are the cells in the inner lens of your eye, the muscle cells of your heart, and the

00:17:35 neurons of your cerebral cortex.

00:17:37 That's a fancy word for the outer layers of your brain.

00:17:42 Millennials are people who are now between 25 and 40 years old.

00:17:46 And they tend to be more forgetful than older people.

00:17:49 The main reason for this phenomenon is higher levels of stress these folks have.

00:17:56 People with albinism have little to no melanin.

00:17:59 That's the pigment that gives color to your hair, skin, and eyes.

00:18:02 It's a rare condition.

00:18:04 In the US, only 1 in 18,000 to 20,000 people is born with albinism.

00:18:10 But there's also ocular albinism, and it's even rarer.

00:18:13 Experts think only 1 in 50,000 people has ocular albinism.

00:18:19 During just one day, the blood in your body travels over 12,000 miles.

00:18:25 That's half as long as the distance around Earth.

00:18:28 Almost 25% of your body's cholesterol is in your brain.

00:18:33 This substance is crucial for your memory and learning abilities.

00:18:36 But the blood-brain barrier doesn't allow your brain cells to get cholesterol from the

00:18:41 blood.

00:18:42 That's why your brain produces its own kind of cholesterol.

00:18:46 Paradoxically, even though your teeth are a part of the skeletal system, they don't

00:18:51 count as bones.

00:18:52 It might be because they, sadly, can't regenerate.

00:18:56 But if a bone is broken, it heals on its own by producing new bone cells.

00:19:02 Your eyes can see something for a mere 13 milliseconds, and it'll be enough time for

00:19:07 your brain to process the image.

00:19:09 For comparison, the average blink lasts from 100 to 400 milliseconds.

00:19:16 Bright sunlight makes 17 to 35% of people sneeze.

00:19:20 This phenomenon is called the photic sneeze reflex.

00:19:24 Your fingers are extremely sensitive.

00:19:27 They can feel objects that are no bigger than the width of your hair.

00:19:31 If your finger was the size of Earth, you'd still feel the difference between cars and

00:19:35 houses.

00:19:38 If there is a calorie chart in a restaurant, people tend to order less healthy and more

00:19:43 high-calorie food.

00:19:44 They compare the difference between, let's say, a burger and a large serving of Caesar

00:19:49 salad and notice that it isn't that big.

00:19:52 And since the burger seems to be more filling, that's what they order.

00:19:56 But when people don't know that a big portion of salad contains almost as many calories

00:20:01 as the burger, they pick a healthier option.

00:20:06 So get this.

00:20:07 If someone managed to uncoil all the DNA in the human body, it would stretch out to around

00:20:13 10 billion miles.

00:20:14 Hey, do the math.

00:20:16 That's twice the distance from Earth to Pluto.

00:20:18 And that's not the only awesome thing our body is capable of.

00:20:23 Trillions of nerve connections are powering your memory non-stop.

00:20:26 According to studies, after looking at 2,500 images for a mere 3 seconds, most people can

00:20:32 recall if they have seen these pictures with 92% accuracy.

00:20:39 Your body glows, emitting tiny amounts of fairly visible light.

00:20:43 This glow is the product of biochemical reactions going on inside your organism.

00:20:47 The light waxes and wanes throughout the day.

00:20:50 And even though it is visible, you can't detect it with the unaided eye.

00:20:55 From 1 to 6 pounds of your body weight is made up of bacteria.

00:20:59 And from 100 million to 1 billion bacteria can live on just one tooth in your mouth.

00:21:05 So please brush.

00:21:07 It's impossible to taste your food without saliva.

00:21:10 All because the chemicals in your food must be dissolved in saliva before they get detected

00:21:15 by your taste buds.

00:21:18 Even though it sounds like a myth, eating too many carrots can indeed turn your skin

00:21:22 orange.

00:21:23 Carrots have high amounts of beta-carotene.

00:21:26 That's a compound that can cause keratinemia.

00:21:28 If you have too much of this compound in your bloodstream, it'll hold on to parts of your

00:21:32 body with thicker skin.

00:21:34 I'm talking about the soles of your feet, your knees, elbows, palms, and even certain

00:21:39 areas around your nose.

00:21:41 But worry not, this condition is not dangerous.

00:21:44 You can easily reverse it by decreasing the amount of beta-carotene-filled foods you consume.

00:21:50 The chin muscles, scientifically known as the mentalis muscles, look pretty quirky,

00:21:56 giving us mixed feelings.

00:21:57 Just look at these creepy tiny tentacles!

00:22:00 And still, they make it possible for us to create all kinds of facial expressions that

00:22:04 involve the lips, chin, and cheeks.

00:22:07 And yes, they are the culprits behind those weird wrinkles and crevices on the skin of

00:22:12 your chinny-chin-chin.

00:22:13 All because these muscles don't pull on themselves, but yank on the skin.

00:22:19 People can live without some organs, leading a normal life.

00:22:22 The human body consists of singular organs and those that come in pairs.

00:22:26 And speaking of the latter, you'll only need one of those to survive.

00:22:31 Your small intestine is actually not so small.

00:22:33 It's taller than you, measuring around 23 feet.

00:22:38 The cornea, that transparent front cover on your eyes, doesn't have any blood supply.

00:22:43 Instead, it receives oxygen directly from the air.

00:22:47 Human beings develop their unique fingerprints very early in life, while they're still

00:22:51 embryos, just 3 months after being conceived.

00:22:54 By the way, even if fingerprints get badly damaged, they tend to grow back to their original

00:22:59 pattern.

00:23:01 All people are born with a diving reflex.

00:23:03 It can get activated and shut bodily functions if one is drowning or is submerged in the

00:23:08 water.

00:23:10 The human brain is by no means smooth, but if you decided to flatten all those wrinkles

00:23:15 covering it, the brain would be the size of a pillowcase.

00:23:18 But not as useful.

00:23:20 Newborn babies only blink once or twice in a minute.

00:23:23 For comparison, a grown-up person blinks at least 10 times within the same time.

00:23:29 Our lungs are the only organs that can float on the water.

00:23:32 All because they're made up of around 300 million balloon-like structures called alveoli.

00:23:37 Also, even if we're perfectly healthy, our lungs are never completely germ-free or sterile.

00:23:44 Your nose is a superhero!

00:23:46 It's your very own heater, filter, and humidifier.

00:23:49 This organ is lined with tiny bone-like shells called turbinates.

00:23:53 They contain blood vessels capable of heating the air and goblet cells that can help humidify

00:23:58 the air.

00:23:59 Also, the air you breathe gets filtered in your nose before going further to your lungs.

00:24:05 Every time you eat something, your esophagus – the organ your food travels through to

00:24:09 reach the stomach – moves in a series of wave-like contractions, pushing the food forward.

00:24:15 This is known as peristalsis.

00:24:17 There's a bond between your digestive system and your brain – the gut-brain axis.

00:24:23 This is why stress or brain issues can affect the way your body digests food.

00:24:28 Even though hiccups are typically harmless and resolve by themselves after a couple of

00:24:33 minutes, they aren't exactly pleasant.

00:24:35 So you should probably know that they might occur because of changes in temperature.

00:24:40 The density of your brain increases throughout your whole life.

00:24:44 All because new neural connections pop up.

00:24:46 They appear because the structure of the brain keeps changing too.

00:24:51 If you don't want to sneeze, press the skin on the bridge of your nose with your fingers.

00:24:56 When you do it, your brain receives an alarm signal.

00:24:59 Pretty quickly, it puts the brake on all those other processes, including the sneezing reflex.

00:25:04 By the way, studies have found that sneezing is your nose's way to reset.

00:25:09 A sneeze reboots the cells that line the inside of your nose.

00:25:13 They're called cilia.

00:25:15 The part of your brain that's responsible for vision is in the back of your head.

00:25:19 Interestingly, the right side of your brain controls the vision on the left side, and

00:25:24 vice versa.

00:25:26 If you're in some loud place, for example, in a club or at a concert, close your ears

00:25:31 to better hear your friends.

00:25:33 Push the tragus, which is that pointy skin-covered cartilage in front of the ear canal, into

00:25:38 your ear.

00:25:39 Then, turn this ear toward your friend.

00:25:42 On average, when a person snores, the sound doesn't get louder than 60 decibels.

00:25:47 That's as loud as a regular conversation.

00:25:50 But sometimes, the noise level can reach 80 decibels.

00:25:53 That's as loud as a working food blender.

00:25:57 Just like salamanders regrow their tails, humans might be able to regenerate cartilage.

00:26:02 That's the rubber-like stuff surrounding your joints.

00:26:05 Scientists have recently discovered that cartilage could repair itself.

00:26:09 This process is likely to be the most effective at the ankle, not that effective in the knee,

00:26:14 and the least effective in the hip.

00:26:17 If a person has asnosmia, which is also called smell blindness, they don't distinguish

00:26:22 and detect smells.

00:26:25 Your eyes never stop moving while taking in visual information.

00:26:28 Otherwise, you wouldn't be able to see the whole picture.

00:26:31 These movements go unnoticed because your brain is a great video editor.

00:26:35 It stabilizes the images and connects tons of fragments into one smooth video.

00:26:42 The liver is the only human organ that can regenerate completely.

00:26:46 Even if it's a mere 25% of the original liver weight, the organ can get back to its

00:26:51 full size.

00:26:53 Your mouth burns when you're snacking on pineapple because while you're eating this

00:26:57 fruit, it's eating you back.

00:26:59 Well, kind of.

00:27:01 Pineapple is the only known food that contains bromelain.

00:27:04 That's an enzyme that breaks down proteins.

00:27:06 Luckily, your stomach acid knows how to deal with the offending enzyme.

00:27:12 We also have bacteria that can produce electricity living in our intestines.

00:27:16 These bacteria give off electrons, which creates tiny electrical currents.

00:27:21 This might be the bacteria's way to generate energy.

00:27:25 Deja vu might actually be something like a brain processing lag.

00:27:31 There's a theory claiming that it might happen when your brain is moving information from

00:27:36 one part to another.

00:27:37 If there's even the tiniest delay in that process, your brain will get the same information

00:27:42 twice.

00:27:43 In this case, it'll process it as an event that happened before.

00:27:47 The DEC2 gene mutation allows people to have just a few hours of sleep a night and still

00:27:53 feel great.

00:27:54 They don't get tired and never sleep in.

00:27:57 On average, such people wake up at 4 or 5 am.

00:28:00 No more than 5% of the world's population has this feature.

00:28:06 Your ears might pop or even hurt when you're on an airplane.

00:28:09 You can solve this problem by simply chewing some gum.

00:28:13 This opens up your eustachian tube.

00:28:15 That's a small passage that connects your throat and your middle ear.

00:28:19 Opening this passage helps equalize the pressure in your ears and puts an end to the popping.

00:28:24 You can also yawn to open up the eustachian tubes.

00:28:28 Your feet are likely to become bigger with time.

00:28:30 Just like your nose.

00:28:31 And your ears.

00:28:32 You see, when people grow older, ligaments and tendons in their feet weaken.

00:28:37 This makes the arches flatter, and the feet become wider and longer.

00:28:43 Unlike our primate pals, many people still have these foot arches.

00:28:47 They help us move.

00:28:49 This arch is like a built-in shock absorber for your feet.

00:28:53 It's what allows us to bounce.

00:28:55 There's another one.

00:28:56 It's called the transverse arch, running side to side on the top of your foot.

00:29:02 Think of it like a bridge that helps keep your foot in shape.

00:29:05 Research says this arch is a big deal too.

00:29:08 It's responsible for about 40% of your foot's stiffness.

00:29:12 Simply put, it's like the scaffolding that holds your foot together.

00:29:16 When scientists snipped the transverse arch, the foot lost a lot of its firmness.

00:29:21 But when they cut the bottom arch, it wasn't that dramatic.

00:29:26 So is it a modern human thing?

00:29:28 Nope.

00:29:29 These arches didn't just pop up yesterday.

00:29:32 The transverse arch has been around for 3 million years.

00:29:36 The bottom arch showed up about 1.8 million years ago.

00:29:41 We might as well continue with another element of our feet before moving up to other parts.

00:29:46 Our pinky toes are also more important than they seem.

00:29:50 Whether you were born without one or have lost it, you can still walk.

00:29:54 But pinky ones are important for keeping us on our feet.

00:29:57 They provide balance.

00:29:59 Inside your foot, you've got 26 bones that team up to make sure you don't topple over.

00:30:05 Small toe is a part of this balance work.

00:30:07 Our ape ancestors needed their toes to grab, claw, and swing from trees.

00:30:13 Today we've traded our tree climbing skills for comfy couches and binge watches.

00:30:17 Okay, let's move up a bit and talk about the appendix.

00:30:22 You might think that it's useless, but nope.

00:30:24 When a human is in their mommy's belly, this organ starts to do its job.

00:30:30 Around the 11th week of development, it starts churning out special cells that produce helpful

00:30:35 hormones and compounds.

00:30:37 The appendix helps train our immune system's troops ensuring they're top-notch defenders.

00:30:42 It also collects all sorts of foreign substances, aka antigens, from our digestive tract.

00:30:48 Yet, as diets evolved, this piece shrank like a deflating balloon.

00:30:54 Unlike most other vestigial structures, the appendix isn't always harmless.

00:31:00 It can turn into an angry little fireball.

00:31:04 By the way, vestigial organs are the ones that have lost their primary ancestral function.

00:31:10 These structures mostly lack an apparent purpose.

00:31:13 Another famous vestigial example is wisdom teeth.

00:31:17 Those are pointless and have been causing us trouble for ages.

00:31:20 Yet nearly 95% of us have them, and 90% might even have to deal with the drama of an impacted

00:31:26 wisdom tooth at some point.

00:31:28 If you don't have them, you might consider yourself lucky.

00:31:32 There's an additional interesting fact about wisdom teeth.

00:31:36 Even though your teeth have a mineral softer than what's in shark teeth, new tests show

00:31:40 that they're just as resilient.

00:31:43 The coating on shark teeth is actually similar in hardness to the enamel on a human wisdom

00:31:48 tooth.

00:31:49 It's because their surfaces are made of mineral crystals held together by proteins.

00:31:54 These prevent them from shattering easily upon impact.

00:31:57 So the difference in how we and sharks use our teeth comes down to their design, not

00:32:02 their toughness.

00:32:04 Anthropologists have examined ancient skeletons.

00:32:07 They think our ancestors needed these extra teeth to chew tough stuff, like roots and

00:32:12 raw meat.

00:32:14 Back then, those extra teeth came in handy.

00:32:17 But then we discovered cooking, and suddenly our food got softer, and our jaws got smaller.

00:32:25 Geneticists have their own take on this subject.

00:32:28 It involves a gene called MYH16, which seems to play a role in both brain size and jaw

00:32:34 characteristics.

00:32:35 Yet, the exact part it played in our evolutionary story is still a bit of a mystery.

00:32:42 Now another pointless thing is the eyelid.

00:32:45 Well, not the regular eyelid.

00:32:48 You know, that little pink thing hiding in the corner of your eye.

00:32:52 Birds and some other furry pals use it to fend off dust and debris trying to mess with

00:32:57 their eyes.

00:32:58 But in us humans, it's mostly vestigial.

00:33:02 Meet the Palmaris Longus.

00:33:05 About 85% of us still carry it around.

00:33:09 Maybe you also have it.

00:33:11 You can test it by putting your hand on a flat surface and making your pinky and thumb

00:33:15 meet.

00:33:16 If you spot a little tendon band doing the limbo in the middle of your wrist, then you've

00:33:21 found it.

00:33:22 It was there for gripping stuff and swinging around like Tarzan.

00:33:26 We can carry on with the grasping trick.

00:33:29 Even before you're born, around 16 weeks into your time inside your mom's tummy, you're

00:33:35 already practicing your grip.

00:33:38 You start by grabbing onto the umbilical cord.

00:33:41 When you finally arrive in the world, this reflex helps you hold onto things.

00:33:46 Fun fact, small monkeys can hang on one hand for ages, thanks to a similar trick.

00:33:52 Yet, we humans lose this super grip when we're around 3 months old.

00:33:58 When you're still in your mother's womb, you also have a mini tail.

00:34:02 But as you grow, it disappears, and those tiny vertebrae become your tailbone or coccyx.

00:34:09 Humans and our ape cousins don't have tails like other animals.

00:34:13 Our ears too have vestigial muscles.

00:34:16 They help animals hear better and express their feelings.

00:34:20 But in humans, these ear muscles don't do much.

00:34:25 We've figured out other ways to listen and show our emotions.

00:34:29 Yet some of us can still wiggle our ears with practice.

00:34:33 Surprisingly, toenails also count as a vestigial thing.

00:34:37 I mean, they function as the initial line of defense.

00:34:40 They protect the body against harmful microorganisms.

00:34:44 In our evolutionary journey, we used our fingernails and toenails for defense, digging, and climbing.

00:34:50 In the modern world, fingernails still come to our rescue, whether it's for peeling fruit

00:34:55 or that sweet sensation of scratching an itch.

00:34:58 Yet, toenails have retired.

00:35:00 But hey, we can apply nail polish to them.

00:35:04 For fashion's sake, they certainly work for many people.

00:35:08 It's not just humans who have useless limbs or organs.

00:35:12 In 1798, an anatomist examined a peculiar bird incapable of flying.

00:35:18 He documented his observations.

00:35:20 This avian species was none other than an ostrich.

00:35:24 Ostriches and cassowaries are just a few examples of birds possessing vestigial wings.

00:35:31 Anatomically speaking, these are rudimentary wings, incapable of granting flight to these

00:35:36 hefty creatures.

00:35:37 Yet, they aren't entirely devoid of function.

00:35:41 They serve the purpose of maintaining balance during rapid running.

00:35:44 Plus, they elaborate courtship displays, helping birds attract potential mates.

00:35:49 Now, when it comes to animals, a lot of them glow, too.

00:35:53 Around 76% of ocean animals, including jellyfish, worms, sharks, and sea stars, are bioluminescent.

00:36:01 They have a compound called luciferin that reacts with oxygen to create light.

00:36:06 And for them, it serves such purposes as stunning predators, attracting prey, or warning others

00:36:11 of danger.

00:36:13 We humans can glow, too.

00:36:16 Unfortunately, this glow is super faint.

00:36:19 Our eyes can't see it.

00:36:21 Our bodies emit light, but it's about a thousand times dimmer than what our eyes can detect.

00:36:27 Scientists found that our glow changes throughout the day.

00:36:31 It's the faintest in the morning and the brightest in the late afternoon.

00:36:35 Our faces glow more than the rest of our bodies.

00:36:38 They think it's because our faces get more sun exposure and have melanin, which has components

00:36:42 that can boost light production.

00:36:45 Some body tricks distinguish us from the rest of the animal kingdom.

00:36:49 For instance, do you know that humans are the only animals capable of blushing?

00:36:54 It seems we've got the exclusive rights to this rosy-cheeked phenomenon.

00:36:59 When we find ourselves in an embarrassing situation, our blood vessels dilate.

00:37:05 That's what gives us those blushes.

00:37:08 Embarrassment is a pretty complex emotion.

00:37:11 It's all about understanding what others think of us.

00:37:15 This might be too advanced for other animals.

00:37:18 Interestingly, bald uakari monkeys can also blush, but not in the same sense.

00:37:24 For them, this is a show of their good health.

00:37:28 Speaking of good health, we should honor our gut.

00:37:31 Your gut includes the stomach, liver, and more.

00:37:35 It's often called the second brain.

00:37:37 This second brain has its own nervous system.

00:37:41 It has 100 million messengers.

00:37:43 They send info to the rest of your body.

00:37:46 Even if the gut-brain connection is cut, it keeps working.

00:37:50 It ensures your digestive system functions on its own.

00:37:57 You know what, in 10 years from now, you'll be a completely different person.

00:38:01 Well, at least your skeleton will be.

00:38:04 To reach its adult size, your skeleton went through a process called modeling, which means

00:38:09 the development of growth and formation.

00:38:12 Turns out it regenerates completely once every 10 years or so.

00:38:16 This entire process ensures you always have healthy bone cells, which can support you

00:38:21 and provide calcium to your body.

00:38:24 And speaking of ways the body regenerates, every second you make 25 million new cells.

00:38:29 I'll do the math for you.

00:38:31 Okay, that means in about 15 seconds, you'll have made more cells than there are people

00:38:36 in the United States.

00:38:37 Think about that the next time you feel you haven't been productive enough.

00:38:43 Some animals have eyes that need to adapt to hot climates.

00:38:46 Like camels, for example.

00:38:48 Their eyes feature a third eyelid, but these sweep across from the corner of each eye.

00:38:54 Because their environment is filled with small particles, they need to clean their eyes more

00:38:58 frequently than other species.

00:39:01 Now see that little pink thing in the corner of your eye?

00:39:04 It's also a third eyelid.

00:39:06 Well, a vestige at least.

00:39:08 In humans, the third eyelid is unnecessary because it no longer serves its original purpose.

00:39:15 Next time you're tuning in to your favorite song, try to pay some attention to your heartbeat.

00:39:21 If you listen closely, you'll notice that sometimes your heartbeat may synchronize with

00:39:26 the rhythm of the song.

00:39:28 Now not all genres of music have this special ability.

00:39:32 But some tunes trigger the release of dopamine, or the "happy hormone."

00:39:36 This effect may give you a lower heart rate, breathing rate, and blood pressure.

00:39:42 And speaking of that healthy ticker of yours, just in case you're wondering, it beats on

00:39:46 average about 75 times per minute.

00:39:50 This means each year, a human heart can pump enough blood to fill an Olympic-sized pool

00:39:55 if that were a thing.

00:39:57 What's even more fascinating is that if you were to connect all your blood vessels end-to-end,

00:40:02 it would be able to circle the Earth 2 ½ times.

00:40:06 But that's not good for your own health, so don't do that.

00:40:10 Your heart can also continue to beat even if it's removed from the body.

00:40:14 That's because it has its own internal battery, which allows it to beat as long as it receives

00:40:19 oxygen.

00:40:21 If you regularly have your nails done at a salon, you've probably noticed you need more

00:40:26 appointments for your fingers than your toes.

00:40:29 That's because fingernails do grow faster.

00:40:31 The definitive scientific answer is still up for debate, but many specialists think

00:40:36 it's because fingernails used to be claws – somewhere back in our ancient history.

00:40:41 These days, they're flatter and have widened a bit, and it all happened when primates started

00:40:46 using tools in their day-to-day lives, like stones and branches, so there was less use

00:40:51 for claws.

00:40:53 Once they got flatter, it meant nails wouldn't have gotten in the way if primates wanted

00:40:57 to use the palms of their hands.

00:41:01 As for why fingernails grow faster than toenails, the short answer may be the fact that we use

00:41:06 our hands more than your feet.

00:41:08 As such, our fingernails are more exposed, and we may have evolved to grow them faster.

00:41:13 The more you use a certain part of your body, the more it becomes exposed to damage.

00:41:19 So for me, I'm in danger of my mouth falling off.

00:41:25 Getting back to our hands, it's about time we give a nice shout-out to our humble pinkies.

00:41:30 We don't see them as being really that important, since we don't use them for holding objects,

00:41:35 eating, or writing.

00:41:37 But recent studies have shown that losing the pinky on our dominant hands would have

00:41:41 a devastating effect.

00:41:44 Specialists haven't gathered enough data to supply specific numbers, but from what

00:41:48 they've learned so far, losing our pinky would weaken our grip strength considerably,

00:41:53 even if it's the lesser-used finger.

00:41:56 Adding the ring finger to that, and the effect would be worse for our grip strength.

00:42:02 Another recent study done in the UK has shown that only about 40% of people are happy with

00:42:07 how their nose looks.

00:42:10 Regardless of how you feel about it, the human nose is a real-life superhero.

00:42:15 That's because it acts as a heater, filter, and humidifier all at once.

00:42:20 Inside each nostril, there are small, shelf-like bones that feature blood vessels.

00:42:25 They heat the air up before it reaches other parts of our respiratory system.

00:42:30 The mucus that's inside there handles making the air more humid.

00:42:35 As for the filtering part, that's why we have nose hairs.

00:42:38 Small particles get stuck on these small hairs, which helps prevent pollen, spores, viruses,

00:42:43 or bacteria from reaching our lungs.

00:42:47 Now when watching cartoons, we're led to believe that the sound our heart makes is

00:42:51 because it's touching its environment while beating.

00:42:54 Well, it turns out that sound is actually made by the opening and closing of the heart

00:42:59 valves.

00:43:00 They're like small doors inside our hearts that open and close to pump blood correctly

00:43:05 from one side of the heart to the other.

00:43:08 For our bodies to work, blood needs to move at the right time and in the right direction.

00:43:13 Or else…

00:43:14 Now let's talk teeth.

00:43:17 Throughout your entire life, you'll probably spend up to 40 days total just brushing your

00:43:22 teeth.

00:43:23 And in case you're still wondering, teeth are not in fact bones, even though they do

00:43:28 have a lot in common.

00:43:29 One of the primary differences between bones and teeth is that our bones can regenerate

00:43:34 – they are living tissue.

00:43:36 Our teeth are not, and they remain permanently damaged once broken.

00:43:41 Here's another shocker.

00:43:43 We are the only species on this planet to have a chin.

00:43:46 There's still some debate about this subject in the scientific community, but one of the

00:43:51 reasons why seems to be to make our jaws stronger.

00:43:56 As humans have continued to evolve, their teeth and the muscles in their jaws got smaller

00:44:00 and smaller.

00:44:01 So they needed something to help with increased jaw resistance.

00:44:07 Most of us have developed some specific traits depending on the area of the globe in which

00:44:12 we live.

00:44:13 But there is a group of people, specifically those who live in higher altitudes, that develop

00:44:18 some pretty cool traits.

00:44:20 That's because high-altitude environments come with less oxygen.

00:44:24 Not only do these people survive in these locations, but they've adapted so well that

00:44:29 they actually thrive.

00:44:31 In the Andes Mountains of South America, people have evolved red blood cells that can carry

00:44:36 much more oxygen.

00:44:38 It makes their overall circulatory system much more efficient.

00:44:42 People living in Tibet have to endure similar conditions, but surprisingly, they have adapted

00:44:47 differently.

00:44:48 In Tibet, they can take more breaths so that they can properly oxygenate their bodies.

00:44:55 You've probably heard the myth about dreams only lasting a couple of seconds in reality.

00:45:00 Turns out that yes, some of them do, but not all dreams are the same.

00:45:05 There are a lot of things we don't understand yet about how we dream.

00:45:09 What we do know is that they mainly happen during the rapid eye movement, or REM, stage

00:45:14 of sleep.

00:45:15 During this time, your brain is more active, about as active as it is when you're awake.

00:45:20 And it's named REM because, during the sleep stage, your eyes tend to move a lot.

00:45:26 Dreams can happen during the other stages of sleep too, but you're less likely to

00:45:30 remember them.

00:45:32 As for the length of each dream, they can go from a few seconds to even 20-30 minutes.

00:45:38 Also, you're more likely to remember a dream if you've woken during the REM stage.

00:45:43 Most people have 3-5 dreams per night, but some people can have up to 7.

00:45:48 I know, seems unlikely, but remember, you immediately forget most of what you dream.

00:45:55 Just like we have unique fingerprints, we also develop unique tongue prints.

00:46:00 Research has shown that those approximately 10,000 taste buds on our tongues are laid

00:46:05 out in a one-of-a-kind pattern.

00:46:07 Truth is, about 80% of what you believe is taste is actually smell.

00:46:12 That combination of taste and smell that we perceive is what we come to know as flavor.

00:46:18 That's probably because our sense of smell is around 10,000 times more sensitive than

00:46:23 our sense of taste.

00:46:25 Our mouths have also another cool superpower called mouth feel.

00:46:29 With the help of the somatosensory system, it allows us to sense the texture of our food.

00:46:35 The system is activated by physical touches, such as pressure, touch, or vibrations.

00:46:40 It's even sensitive to pain and temperature.

00:46:44 We also use our tongues to identify the size, form, and texture of food, which is crucial

00:46:49 for proper chewing and digestion.

00:46:52 Hey, tongues are also good for wagging, sticking out at certain people, and trumpet playing.

00:47:02 Check out that buff dude over there with the orange skin.

00:47:05 He's been chilling on Mars for a hot minute, which is why he looks like he used the wrong

00:47:08 shade of self-tan.

00:47:09 You see, all those carotenoids in carrots, sweet potatoes, bell peppers, tomatoes, and

00:47:14 pumpkins are protecting him from those UV rays.

00:47:17 The more he eats, the more orange he gets.

00:47:19 And as for his sturdiness, it's all about that Martian gravity.

00:47:24 The gravity here makes us perceive our weight differently.

00:47:27 And if you want to be a boss on Mars, you gotta eat heavily.

00:47:30 Like, if a person weighs 150 pounds on Earth, it feels like no more than 55 pounds on Mars.

00:47:36 So, overeating can help shorten that gravity to weight gap.

00:47:40 Mercury is a whole different thing.

00:47:42 It's hotter than Georgia asphalt during the day, but colder than Elsa's castle at night.

00:47:46 You gotta be made of metal with a high melting point to be able to survive here.

00:47:50 But for us regular humans, we'd be toast.

00:47:53 Literally.

00:47:54 Even though Mercury is the closest planet to the Sun, Venus is still the hottest one.

00:47:59 Life on Venus?

00:48:01 More like life on the Sun's evil twin.

00:48:03 The temperature here typically hovers around 870 degrees Fahrenheit on average.

00:48:08 Surviving at the boiling point of water, or in the extreme heat of Venus, is a challenge

00:48:13 for most earthly species.

00:48:15 Only a select few can endure boiling hot temperatures.

00:48:18 Others rush to Starbucks to grab an iced latte with the first beams of the spring sun.

00:48:23 So no human being can really evolve enough to survive on Venus.

00:48:27 The only creatures that could thrive there are probably tardigrades and those weirdos

00:48:31 who put hot sauce on everything.

00:48:33 You wonder what tardigrades are?

00:48:34 Well, those are miniscule and adorable caterpillar-like creatures that possess remarkable durability.

00:48:40 They can endure boiling water, the depths of a sea trench, and the frigid, lightless

00:48:44 void of space.

00:48:46 Recently tardigrades were included in a scientific study aboard a spacecraft that unfortunately

00:48:51 crashed on the Moon.

00:48:53 Scientists speculate that the tardigrades may have survived the impact.

00:48:56 Hey, would you like to turn into this creature and live on Venus?

00:49:00 We're done with terrestrial planets.

00:49:01 Let's move on to gas giants.

00:49:04 Now look at this dude from Saturn.

00:49:06 He's got flippers and not arms.

00:49:08 He's got small holes with no external ear flaps instead of regular ears.

00:49:12 Most of this gas giant is colder than your ex's heart, as the temperature is about -220F.

00:49:17 You can't walk on it, but you can turn into a snowball or an ice crystal if you're feeling

00:49:22 frisky.

00:49:23 Things are quite similar on Jupiter, so probably turning into a seal and chilling there is

00:49:27 not that bad of an idea.

00:49:29 At least you can live there rent-free.

00:49:30 And don't even get me started on Neptune and Uranus.

00:49:35 These guys are ice giants with no solid surface, so those sharp-clawed dudes you see in movies?

00:49:40 Yeah, they don't exist.

00:49:42 Plus these two ain't exactly hospitable to life.

00:49:44 I'll stick to my sweet potatoes on Mars.

00:49:46 Thank you very much.

00:49:49 The human body is this perfectly balanced machine, right?

00:49:52 Well, not when I'm using it.

00:49:54 Normally, all its parts work seamlessly together to keep us thriving and, well, alive.

00:50:01 Each of our organs is essential for our day-to-day activities, from breathing, walking, talking,

00:50:07 and coming up with bright ideas that push humanity forward.

00:50:11 But are they really essential?

00:50:13 Do we really need all those body parts, or are some of them just ancient relics that

00:50:18 we just got stuck with in this weird game of evolution?

00:50:22 Take wisdom teeth, for example.

00:50:24 Nah, somebody already took mine.

00:50:26 Yep, they're those pairs of teeth stuck in the back of your mouth you often have to go

00:50:31 to the dentist for.

00:50:32 They're also known as third molars, and while they can be used to chew food, a lot

00:50:37 of people think they're just unnecessary.

00:50:40 And get this – around 22% of people worldwide don't even have all four of them.

00:50:46 When they do grow in, they're the most likely to become impacted, which means they get stuck

00:50:51 in the jawbone sideways and can't properly come through the gums.

00:50:55 It's all because our jaws are often too small to accommodate these extra guys.

00:51:01 Some smart scientists think that's because we've evolved to have smaller jaws over

00:51:05 time.

00:51:06 Recent evidence also shows that what we eat as kids might also be to blame, but it's

00:51:11 hard to know for sure.

00:51:13 Apparently, munching on hard-to-chew foods like raw veggies and nuts can actually stimulate

00:51:18 jaw growth, while eating soft processed foods can kinda stunt it.

00:51:23 And that leaves little space for our back teeth to come in and, you know, do their thing.

00:51:28 Will they disappear altogether in the future?

00:51:31 I guess we human mammals will just have to wait and see.

00:51:34 Now let's talk about the vomeronasal organ, or as I like to call it, the nose's secret

00:51:40 instrument.

00:51:41 You see, rodents and other mammals have this awesome ability to communicate with each other

00:51:46 using chemical signals called pheromones.

00:51:49 And guess what?

00:51:50 They have a special organ called the vomeronasal organ, or VNO, that helps them detect these

00:51:56 pheromones.

00:51:57 Here's where it gets interesting.

00:52:00 While most adult humans have something resembling a VNO in their nose, it turns out that it's

00:52:06 basically a useless remnant.

00:52:09 Neuroscientists even say that if you look at the anatomy of this organ, you won't see

00:52:12 any cells that resemble those of similar organs from other mammals.

00:52:17 Also, this organ in humans doesn't seem to be communicating with the brain either.

00:52:22 Now it's not all bad news.

00:52:24 Even though the human VNO is pretty useless, it looks like it still might respond to some

00:52:29 pheromones.

00:52:31 Will humans keep this organ on their evolutionary to-do list?

00:52:35 For now, I'd place it in the maybe pile.

00:52:38 Now here's a tail.

00:52:40 Animals that feature tails need these structures for a lot of things.

00:52:44 Some need it for balance, others for navigation, while some need it to attract potential partners.

00:52:51 But did you know that when we're just a few weeks old in our mother's belly, we actually

00:52:55 have tails too?

00:52:57 That's right, we have a whole little tail complete with vertebrae.

00:53:01 As we develop, that tail magically disappears, and we're left with our trusty tail bone.

00:53:07 Humans and apes are unique in that we don't have tails, unlike other primates.

00:53:12 It's a mystery why apes lost their tails, but we can all agree that it makes us stand

00:53:17 out in a crowd.

00:53:19 However, once in a blue moon, a human is born with a little vestigial tail.

00:53:24 Cute, right?

00:53:25 Well, don't get too excited, because these tails don't have vertebrae and can sometimes

00:53:30 be associated with a tricky condition of the spine.

00:53:34 Either way, these tails are usually harmless and can be easily removed with a quick surgery.

00:53:40 And let's be honest, it's not like we're going to miss it.

00:53:43 After all, who needs a tail when you have arms and legs to get around?

00:53:48 Plus, can you imagine trying to find pants that fit with a tail sticking out the back?

00:53:53 Not a good look.

00:53:54 There's little to no chance humans will end up needing tails in the future, so I'm

00:53:59 guessing the tail bones are bye-bye in future generations.

00:54:03 Humans also have a funny little fold of membrane in the inner corner of the eyes called the

00:54:09 plica semilunaris.

00:54:10 It's basically what's left of a third eyelid, which is still found in some animals, like

00:54:16 gorillas and other primates.

00:54:18 But here's the funny thing.

00:54:20 Even our close relatives, the chimpanzees, have this little fold that appears to be useless

00:54:25 too.

00:54:26 So, we're not alone in this eye-quirkiness.

00:54:30 Speaking of unusual membranes, they serve a variety of functions in different animals,

00:54:35 such as protecting the eye from dirt and moisture, or hiding the iris from predators.

00:54:41 Some species can even see through their transparent membranes when they're underwater or underground.

00:54:47 The reasons why we humans lost our third eyelid is still a bit of a mystery.

00:54:52 Maybe changes in our habitat and eye physiology made it unnecessary, or maybe we just evolved

00:54:58 to be too cool for a third eyelid.

00:55:01 Who knows?

00:55:02 With or without vestigial organs, it's interesting to imagine what humans might look like in

00:55:08 the future.

00:55:09 Many organs have become obsolete because of our lifestyle changes.

00:55:13 Care to have a peek into what we might look like in the future?

00:55:17 And in the same vein, or artery, have you heard of the concept of "tech's claw"?

00:55:21 It's where you spend so much time typing on your phone or laptop that your hand starts

00:55:26 to cramp up like a claw.

00:55:28 And that's just one of the physical changes that could happen to us if we don't take

00:55:32 care of our bodies in this tech-heavy world.

00:55:36 But it's not just our hands that are affected.

00:55:39 We could end up with 90-degree elbows from constantly holding our devices at that angle,

00:55:44 and even a smaller brain from all the distractions and information overload.

00:55:49 Now I know what you're thinking, "We just can't give up technology and go back to the

00:55:53 Stone Age!"

00:55:54 And you're right, we don't have to.

00:55:57 But we do need to be aware of the potential negative effects and take steps to reduce

00:56:01 their damage.

00:56:02 That's why a team of designers put their creative efforts together to present Mindy,

00:56:08 a future human whose body has physically changed due to the constant and never-ending use of

00:56:13 smartphones, laptops, and other types of maniacal devices.

00:56:18 While Mindy's exaggerated changes may not be in our future, the concerns behind them

00:56:23 are real.

00:56:24 So what can we do?

00:56:26 Well, one suggestion is to take regular breaks from our screens and stretch our legs a little.

00:56:32 Maybe even encourage some office yoga or dance parties to get the blood flowing.

00:56:37 We don't have to give up technology completely, but we do need to be mindful of its effects

00:56:42 on our bodies and minds.

00:56:44 Many years in the future, we might even get smaller in size.

00:56:48 One scientist reckons that if we were smaller, our bodies would need less energy, which would

00:56:53 come in super handy in our increasingly crowded planet.

00:56:57 It's funny to think about how different our lives are now compared to when we were hunter-gatherers.

00:57:04 Back then, we only had to interact with a handful of people each day.

00:57:08 But now, remembering people's names is a super important trait, and it might even be

00:57:13 something we grow to become better at.

00:57:16 Or technology might actually play a role in our evolution.

00:57:20 Scientists believe that we could one day have implants in our brains that help us remember

00:57:25 people's names.

00:57:26 It's like having a biological phone book directly in your body.

00:57:29 Wouldn't that be cool?

00:57:31 Maybe, who knows, maybe in the future, we'll even have visible technology as part of our

00:57:36 appearance.

00:57:37 Imagine having an artificial eye that can see different colors and visuals.

00:57:43 And don't even get me started on what we might look like if we colonized Mars.

00:57:47 With the lower gravity, our bodies could change in all sorts of ways.

00:57:52 We might have longer arms and legs, or even insulating body hair like our Neanderthal

00:57:57 ancestors.

00:57:58 It's hard to pinpoint what we might look like in the future without very precise data

00:58:03 to back the models up.

00:58:05 But it's fair to say these changes will be interesting, to say the least.

00:58:09 As for me, well, it's too late to say the least.

00:58:11 I've said over 1,400 words here already.

00:58:16 Hey, not to freak you out or anything, but every second, your body creates 25 million

00:58:24 new cells.

00:58:25 I'll do the math for you.

00:58:27 That means that in about 15 seconds, you'll have produced more cells than there are people

00:58:31 in the United States.

00:58:33 Think about that next time you feel you haven't been productive enough.

00:58:37 It may account for only 2% of our body mass, but our brains actually take up 20% of our

00:58:43 blood supply and oxygen.

00:58:45 Our brains can also produce enough energy to supply a light bulb.

00:58:48 That is, when we're awake.

00:58:51 Ever thought about what the largest human organ is?

00:58:53 It's your skin, and it's thickest on the palms of your hands and soles of your feet.

00:58:59 I know, I know, I hate dusting too, but you are particularly responsible for that layer

00:59:04 of fluff on your TV screen, you know.

00:59:07 Every human being sheds about 600,000 particles of skin every hour, and most of the dust around

00:59:13 your house is actually composed of that.

00:59:16 So yes, we're all rather flaky.

00:59:19 These days, it's considered more of a beauty mark, but the reason why people are born with

00:59:23 a Cupid's bow is actually quite intriguing.

00:59:27 As our features start to develop before we're even born, it appears that the Cupid's bow

00:59:31 is actually the place where our face, well, zips up.

00:59:36 The right side of the face and the left side of the face, that is.

00:59:39 While in humans, it may not be that obvious.

00:59:41 If you look at your dog's nose, you'll see it has a straight vertical line just under

00:59:46 the nostrils.

00:59:47 That's right, dogs have this zip too!

00:59:50 Did you know you were born with more bones than you have today?

00:59:53 At birth, we have somewhere around 300 bones, but as we age, some of them fuse together.

01:00:00 That's why in adulthood, we end up having about 200 bones.

01:00:05 Although your teeth are technically part of your skeletal system, they're not actually

01:00:08 bones.

01:00:09 They do look sort of similar and do share some characteristics, like being the hardest

01:00:14 element in your body.

01:00:15 Why the misconception though?

01:00:17 Well, it's mostly because both teeth and bones contain calcium.

01:00:21 To be a bit more specific, about 99% of the body's calcium is in your bones and teeth.

01:00:27 The remaining calcium is in your bloodstream.

01:00:29 So what makes them different, you might ask?

01:00:32 It's in how the bones and teeth heal and how you should take care of them.

01:00:36 While bones can repair and heal themselves, your teeth aren't able to do that.

01:00:41 That's why we have dentists.

01:00:43 We don't only have unique fingerprints, our tongues are one of a kind as well.

01:00:48 Research has shown that those approximately 10,000 taste buds on our tongues are laid

01:00:53 out in a unique pattern, specific for each one of us.

01:00:56 About 80% of what you believe is taste is actually smell.

01:01:01 The combination of taste and smell that we perceive is what we come to know as flavor.

01:01:06 That's probably because our sense of smell is around 10,000 times stronger than our sense

01:01:11 of taste.

01:01:13 So the next time you're tuning in your favorite song, try to pay some attention to your heartbeat.

01:01:18 Do you hear that?

01:01:19 Yep, that's right.

01:01:21 While listening to some music, your heartbeat will sync with the rhythm of the song.

01:01:26 And speaking of that healthy ticker of yours, just in case you're wondering, it beats on

01:01:30 average about 75 times per minute.

01:01:33 This means that in any given year, a human heart can pump enough blood to fill an Olympic-sized

01:01:38 pool.

01:01:39 What's even more fascinating is that if you were to connect all your blood vessels end-to-end,

01:01:44 you'd be able to circle the Earth four times.

01:01:47 But that would really hurt, so don't try that.

01:01:50 We are the only species on this planet to have a chin.

01:01:53 There's still some debate around this subject in the scientific community, but one of the

01:01:57 reasons seems to be to make our jaws stronger.

01:02:01 As humans have continued to evolve, their teeth and the muscles in their jaws got smaller

01:02:06 and smaller.

01:02:07 So they needed something to help with increased jaw resistance.

01:02:11 That transparent part of your eye is called the cornea, and it helps the light go through.

01:02:16 It's also the only part of your body that isn't connected to any blood supply.

01:02:21 Why?

01:02:22 Because it's especially designed to get its oxygen straight from the surrounding atmosphere.

01:02:27 If you took out all the fat found in a healthy human body, it would be enough to make 7 bars

01:02:32 of soap.

01:02:33 We also produce enough saliva in our lifetimes to fill two swimming pools.

01:02:38 Great expectorations!

01:02:40 Ever wondered how much we actually eat during our whole lifetimes?

01:02:44 I'll spare you the math.

01:02:46 An average-sized person eats nearly 66,000 pounds of food throughout the whole course

01:02:51 of their lifetime.

01:02:52 How much is that for scale?

01:02:54 About 6 elephants.

01:02:55 And that ain't peanuts.

01:02:57 Each of us carries around 4 pounds of bacteria on average at any given time in our bodies.

01:03:04 But hey, don't go running to the doctor just yet.

01:03:07 Most of that bacteria is actually good and have specific functions in the human body,

01:03:12 like digestion and our immune systems.

01:03:15 If you want to have an accurate depiction of your height, make sure you measure yourself

01:03:19 in the morning.

01:03:20 That's because you're about 0.4 inches taller right when you wake up.

01:03:25 Trust me, it isn't magic.

01:03:27 It's merely because, throughout the day, the soft cartilage between your spinal bones

01:03:31 gets squashed down and compressed, making you seem shorter by the time you go to bed.

01:03:37 We know that we have some sort of energy moving around our bodies, so we actually do emit

01:03:43 a tiny amount of light.

01:03:44 It's too weak for our own eyes to see, though, but if you think about it, you're actually

01:03:49 glowing as we speak.

01:03:51 The humorist and author Mark Twain once said, "Man is the only animal that blushes, or

01:03:57 needs to."

01:03:58 How true.

01:04:00 But not all humans can blush, and those that do blush to different degrees.

01:04:04 Is there some sort of evolutionary reason for why we blush?

01:04:08 It seems so.

01:04:10 Blushing is a way for us to communicate without using any words, just like dogs wag their

01:04:14 tails when they're happy or excited.

01:04:16 So basically, blushing can be translated to "I'm embarrassed."

01:04:21 Similar to how we shiver when we're cold.

01:04:24 If the human eye was a camera, it would have about 576 megapixels.

01:04:29 Our vision of the world changes throughout our lives.

01:04:32 As soon as we're born, we see the world upside down for a bit.

01:04:35 Our brain is programmed to show the inverted image formed on our retina by the convict's

01:04:40 eye lens.

01:04:41 But that doesn't kick in immediately after birth.

01:04:44 Hey, I'm sure you enjoy that weekly cardio and weightlifting, but the strongest muscle

01:04:49 in the human body is definitely not the one you've been working on.

01:04:53 It's actually in your jaws.

01:04:55 Your jaws are designed similarly to a nutcracker.

01:04:58 Why?

01:04:59 So you can get powerful bites with as little energy as possible.

01:05:03 The fastest muscle is located in your eyes.

01:05:06 That's probably how we came up with the expression "in the blink of an eye" for

01:05:10 when something happens really quickly.

01:05:13 Did you know that your nose comes with a built-in reset feature?

01:05:17 It happens when you sneeze.

01:05:19 Sneezing is basically your nose's way of getting rid of all the bad particles it has

01:05:23 inhaled up to a certain point.

01:05:25 If you think that's bad, it's not.

01:05:28 Did you also think your pinky finger is something weak and pretty much useless?

01:05:32 Well, it actually packs up to 50% of the strength in your hand.

01:05:37 We still haven't figured out precisely why people yawn.

01:05:41 We aren't the only creatures to do it.

01:05:43 Baboons, guinea pigs, and the Siamese fighting fish yawn to warn other animals to stay away.

01:05:48 Penguins seem to yawn during courtship rituals, and snakes yawn at times after a good meal.

01:05:54 Boy, there's a happy snake!

01:05:56 Some theories suggest it helps us get more oxygen in, while others indicate that it helps

01:06:00 with regulating our body temperatures.

01:06:03 Either way, we still don't know for sure.

01:06:06 Our ears and noses are the only organs that continue to grow throughout our lifetimes.

01:06:11 Our eyes stay more or less the same size as we grow up.

01:06:15 By the time we're 3 months old, our corneas should technically reach their full size.

01:06:21 You have as much hair as a monkey.

01:06:23 I don't mean to be insulting, but your fingerprints are not unique.

01:06:28 You can hear better after you cover your ears.

01:06:31 Can these statements be true, or are they nothing but myths?

01:06:35 When a person is lying, their own nose can give them away.

01:06:39 Can it be true?

01:06:45 Yep.

01:06:49 Researchers from the University of Granada have discovered that when a person tells a

01:06:52 lie, the temperature around their nose and in the inner corners of their eyes rises.

01:06:58 This phenomenon got named the "Pinocchio effect."

01:07:02 Hey, how about this one?

01:07:04 People can have as many hairs on their body as chimpanzees.

01:07:08 Can you believe this?

01:07:13 Surprisingly, this one's true too.

01:07:18 The hair count of a person and a chimp, or any other ape of our size, is approximately

01:07:23 the same.

01:07:24 The only difference is that human body hair is quite fine and often colorless.

01:07:29 This makes it hard to see the sheer number of hairs.

01:07:33 Your lungs are identical.

01:07:35 It sounds reasonable, but is it true?

01:07:40 Well, it's nothing but a myth.

01:07:46 Your left lung consists of two lobes, while your right lung is divided into three parts.

01:07:51 Plus, the lung on the left is a bit smaller.

01:07:54 It has to, to make room for your heart.

01:07:57 By the way, your lungs also contain around 1,500 miles of airways.

01:08:02 That's more than half the distance between New York and Los Angeles.

01:08:06 There are also more than 300 million alveoli, tiny balloon-shaped air sacs, in your lungs.

01:08:13 I bet you've heard this one before.

01:08:15 Carrots can make your eyesight better.

01:08:17 True or myth?

01:08:22 Unfortunately, this idea isn't true.

01:08:27 Neither can carrots get you better nighttime vision.

01:08:30 Carrots are indeed packed with vitamin A. It benefits your body and protects your eyes.

01:08:35 But even these veggies can't save you from wearing glasses if you need them.

01:08:40 Some people sneeze when looking at the sun.

01:08:42 Now, do they?

01:08:46 Yes, that's true.

01:08:53 About 25% of people have an interesting reaction to sunlight.

01:08:56 They sneeze.

01:08:58 This phenomenon even has its own name – the photic sneeze reflex.

01:09:04 Shaving body hair makes it grow darker and thicker.

01:09:07 Is it the truth?

01:09:11 Don't worry, that's just a myth.

01:09:16 It might look as if your body hair has changed in thickness, rate of growth, or even color

01:09:21 after getting shaved.

01:09:23 But it's just an illusion.

01:09:25 Shaving makes the tips of hair follicles blunt.

01:09:27 That's why they look rougher and darker than usual.

01:09:30 But once your hair grows in again, it'll start to look the same as it did before you

01:09:35 shaved it.

01:09:37 You have unique fingerprints.

01:09:40 This one must be true, right?

01:09:46 The problem with this statement is that scientists can't prove that each set of fingerprints

01:09:51 is absolutely unique.

01:09:53 It does seem to people, but it's impossible to check.

01:09:56 And while this is improbable, people with identical fingerprints can actually turn out

01:10:00 to be real.

01:10:02 People have more than 5 senses.

01:10:05 Is it an appealing myth or reality?

01:10:13 There are 5 most obvious senses – vision, smell, touch, hearing, and taste.

01:10:19 But how about thermoception – the sense of heat?

01:10:22 Noceoception – the perception of pain?

01:10:25 Or the perception of your body awareness?

01:10:28 Proprioception – close your eyes and touch your nose?

01:10:31 Got it?

01:10:32 That's proprioception and action.

01:10:34 This list can be much longer.

01:10:36 Some experts state people have from 21 to 53 senses.

01:10:42 Your fingers actually get pruney after you spend too much time in the water for your

01:10:46 safety.

01:10:47 Is it true?

01:10:48 Let's check it out.

01:10:54 Scientists believe so, but first things first.

01:10:57 Pruney fingers are caused by narrowing blood vessels.

01:11:00 When you stay in the water for a long time, your nervous system makes your blood vessels

01:11:04 shrink.

01:11:05 Your body sends the blood away from that area, and this loss of blood makes your vessels

01:11:10 thinner.

01:11:11 The skin starts folding over them, forming those funny wrinkles.

01:11:15 Scientists aren't 100% sure, but they think this process occurs to help you have a better

01:11:19 grip when your hands and feet are wet.

01:11:23 People only use 10% of their brains.

01:11:25 Oh, how I wish it was just a myth!

01:11:33 And it is!

01:11:34 Apparently, you use almost 100% of your brain every day.

01:11:39 This organ is active all the time, even when you're asleep.

01:11:43 When you're snoozing, your frontal cortex, which is responsible for higher-level thinking,

01:11:48 and the areas that help you sense your surroundings, are still doing their job.

01:11:53 For some people, the world is much brighter than for others.

01:11:57 Hmm, how come?

01:12:02 That's actually true!

01:12:05 There are three kinds of cone cells in the average person's eyes.

01:12:09 These cones help to recognize the colors in the blue, red, and green spectrums.

01:12:14 Thanks to them, most people can distinguish around 1 million different shades.

01:12:19 But those with technochromacy have four cones in their eyes.

01:12:23 This feature allows them to see up to 100 million different hues.

01:12:27 This vision anomaly is extremely rare, and women have it more often than men.

01:12:33 But do you know the funniest thing about this?

01:12:35 Most people with technochromacy don't even realize they see the world brighter than others.

01:12:40 Sometimes, you can hear better after closing your ears.

01:12:44 Well, it seems counterproductive, but can it be true?

01:12:52 Indeed, if you're in a loud place, for example, in a club or at a concert, you should close

01:12:59 your ears to hear your friends better.

01:13:01 Push the tragus, which is the pointy skin-covered cartilage in front of your ear canal, into

01:13:06 your ear.

01:13:08 Then turn this ear toward your friend.

01:13:11 Voila!

01:13:12 You can prevent yourself from sneezing.

01:13:14 Oh, that would be very convenient, but maybe it's just a myth.

01:13:21 It's true!

01:13:25 If you don't want to sneeze, press the skin on the bridge of your nose with your fingers.

01:13:30 When you do it, your brain receives an alarm signal.

01:13:33 It immediately puts the brakes on all other processes, including the sneezing reflex.

01:13:38 Okay, you're gonna finish these 5 episodes of your favorite series now and catch up on

01:13:43 sleep later, but can you?

01:13:50 Unfortunately, no.

01:13:54 You can try to catch up on sleep at the weekend or take lots of afternoon naps during the

01:13:59 week, but it won't help.

01:14:01 Your body doesn't work this way.

01:14:03 If you didn't have enough sleep the night before or went to bed really late, sleeping

01:14:08 until noon won't save the day.

01:14:11 Even worse, too much sleep will make you feel groggy.

01:14:15 Some people have more ribs than others.

01:14:17 Is it a myth?

01:14:22 Nah, it's true!

01:14:26 Most people have 12 pairs of ribs, which makes 24 in total.

01:14:31 But 1 in 200 people has an additional 25th rib.

01:14:34 It's called cervical and forms at the base of the neck above the collarbone.

01:14:39 It can grow on the left, right, or even both sides of the body.

01:14:43 Those people who have extra ribs most likely know nothing about this modification.

01:14:47 That's because an extra rib rarely forms completely and can look like a thin strand

01:14:52 of tissue.

01:14:53 In this case, you won't see it even on an X-ray.

01:14:57 You should wait for at least half an hour after eating before you go swimming.

01:15:01 Well, it sounds reasonable, but is it true?

01:15:06 Ah, that's just a myth.

01:15:11 The general idea behind this claim is that eating a large meal makes your blood flow

01:15:15 towards your stomach to help with the digestion process.

01:15:19 At the same time, your muscles don't get enough blood, which leads to cramps.

01:15:24 But in reality, swimming right after having eaten something isn't dangerous at all.

01:15:29 Your blood doesn't get diverted enough for it to cause any serious problems.

01:15:34 Some people's snores can get louder than a working kitchen appliance.

01:15:38 What do you think about this?

01:15:42 Well, on average, when a person snores, the sound doesn't get louder than 60 dB, which

01:15:51 is as loud as a regular conversation.

01:15:54 But sometimes, the noise level can reach 80 dB, and that's as loud as a working food

01:15:59 blender.

01:16:01 Not all people have round pupils.

01:16:04 Can it be true?

01:16:09 Yep, 2 people out of every 10,000 have an unusually shaped pupil.

01:16:17 Most commonly, it resembles a keyhole.

01:16:19 This eye disorder is called coloboma.

01:16:22 Interestingly, some people with this condition don't have any problems with their vision.

01:16:31 You may have this rare body feature already and not know about it since sometimes even

01:16:35 an x-ray can't spot it.

01:16:37 Most of us have 12 pairs of rib bones, which means we were born with 24 ribs.

01:16:43 There are some folks, though, that actually have 25 ribs.

01:16:48 Only 1 in 200 people have this rare extra feature, and it's called a cervical rib.

01:16:54 It generally appears above the first rib, right at the base of the neck and above the

01:16:58 collarbone.

01:16:59 It's nothing to worry about, though.

01:17:02 Most of the time, they're unnoticeable, and if ever painful, they can be safely removed.

01:17:08 Do you know how huskies can sometimes have their eyes in different colors?

01:17:12 Some people come equipped with this rare feature, too.

01:17:15 The medical term for it is heterochromia.

01:17:18 The name comes from the ancient Greek word "heteros," which translates to "different,"

01:17:23 and "chroma," which means "color."

01:17:26 People with this condition can either have complete, central, or partial heterochromia.

01:17:32 The complete type means that the person has two completely different colored eyes, say,

01:17:37 one brown and one green.

01:17:39 Two different colors in the same eye are what specialists call central heterochromia.

01:17:44 A person with a partial heterochromia has just a portion of their eye of a different

01:17:49 color.

01:17:50 You can either be born with this condition or get it, say, after an injury.

01:17:55 Still, it's extremely rare.

01:17:57 Less than 200,000 people are diagnosed with it in the US.

01:18:01 Either way, let's face it, it does look pretty cool!

01:18:06 Speaking of eye color, wanna try guessing what the rarest one is?

01:18:10 I'll spare you the Google search.

01:18:12 It's gray.

01:18:13 Blue eyes may have been your first thought, and they are indeed already pretty rare.

01:18:18 Only around 8 to 17% of the world's population have this eye color.

01:18:23 When it comes to gray eyes, though, they're even more special.

01:18:27 Less than 1% of people have them.

01:18:30 This rare body feature is caused by a lower level of melanin in the eye's layers.

01:18:36 If you're interested in meeting someone with gray eyes, your best chance is in Eastern

01:18:40 and Northern Europe.

01:18:42 Even rarer eye colors are red or violet, but these can sometimes be the result of different

01:18:47 health conditions.

01:18:49 There are people out there who have the superpower of seeing 100 million different colors without

01:18:54 the help of any fancy gadgets.

01:18:57 We see colors thanks to some cells in our eyes named cones.

01:19:01 Most of us have three types of cones to help translate what we see into the colors that

01:19:06 our brain is able to understand.

01:19:09 However, specialists think that there's a small group of people called tetrachromats

01:19:14 who have four types of these cones.

01:19:16 So far, researchers have only been able to identify women with this condition.

01:19:22 That little teardrop-shaped ball hanging in the back of your neck, you know, the one that

01:19:27 helps with swallowing your food, is called a uvula.

01:19:30 The name comes from Latin and translates to "little grape."

01:19:34 Surprisingly enough, around 2% of people are born with a bifid uvula, which means that

01:19:40 this indispensable organ in them is either split or forked.

01:19:44 You sure can surprise others with this cool feature of yours at parties.

01:19:49 Joking aside though, people with this bifid uvula may sometimes have trouble eating, drinking,

01:19:54 and speaking.

01:19:55 They might also have issues with digesting food.

01:19:58 Their speech may also sound a bit unusual, but this depends on how much the uvula is

01:20:03 split.

01:20:05 This particular body feature might not be the perfect trait when going on vacation,

01:20:09 but it does allow people to do more with less sleep.

01:20:13 They say that famous people like Nikola Tesla, Margaret Thatcher, and Winston Churchill had

01:20:18 this super rare feature.

01:20:20 This gene, called the DEC2 gene, helps with regulating our circadian rhythms.

01:20:26 Those are the natural biological clocks that let us know when we should be sleeping or

01:20:31 eating by making us sleepy or hungry.

01:20:34 A person with this rare mutation can basically go through a normal sleep cycle in less time.

01:20:40 They can feel rested even if they slept for only 4-5 hours.

01:20:44 That's one superpower I definitely want to have!

01:20:48 How about a gene mutation that gives you superhero-like bones?

01:20:53 They're basically unbreakable.

01:20:54 It also makes your skin less prone to aging.

01:20:57 Yep, looks like with this feature you can walk away from accidents unharmed and even

01:21:02 withstand the flow of time.

01:21:04 Some other people out there come with a very attractive feature, but it can go unnoticed,

01:21:09 at least at first glance.

01:21:11 They have a little something called distichiasis, which basically means an extra row of eyelashes.

01:21:18 Just in case you're wondering about the medical aspects too, it results from a genetic

01:21:22 mutation of a certain gene.

01:21:24 As beautiful as it may sound, people with that extra eyelash layer can experience some

01:21:29 pretty unpleasant sensations in their eyes and, in some cases, even have problems with

01:21:35 their vision.

01:21:37 If spun glass hair doesn't ring a bell, know that it is, in fact, a condition you

01:21:42 might have.

01:21:43 I know it's pretty self-explanatory, but just FYI, it causes frizzy and dry hair.

01:21:50 It's basically so unmanageable that you literally can't comb it.

01:21:54 It also tends to grow out from the scalp in all directions.

01:21:58 As for coloring, it comes in either bright blonde or silver.

01:22:03 Most of us have hair strands that are cylindrical.

01:22:06 People with this condition have triangular or heart-shaped strands or even flat altogether.

01:22:12 It's extremely rare, with only 100 confirmed cases, but it does become more manageable

01:22:17 with age.

01:22:19 Most of us humans have evolved to have some specific traits depending on the area of the

01:22:23 globe that we live in.

01:22:25 But there is a group of people, specifically those that live in higher altitudes, that

01:22:30 developed some pretty cool traits.

01:22:32 Let me explain.

01:22:33 High-altitude environments come with less oxygen.

01:22:37 Not only do these people survive in these locations, but they've adapted to actually

01:22:41 thrive out there.

01:22:43 For example, those living in the Andes Mountains of South America have red blood cells that

01:22:48 can carry much more oxygen.

01:22:51 It makes their overall circulatory system a lot more efficient.

01:22:55 People living in similar conditions in other parts of the world have also adapted in their

01:22:59 own way.

01:23:00 They're able to take more breaths so that they can properly supply their bodies with

01:23:05 oxygen.

01:23:07 This one is very important when it comes to looks but means little in terms of a person's

01:23:12 overall health.

01:23:13 I'm talking about poggeboldism.

01:23:17 Those who have it lack melanocytes, those cells that produce hair pigment in some parts

01:23:22 of their hair.

01:23:23 It's most common above the forehead in front of their hairline, but it can also appear

01:23:28 on the eyebrows or eyelashes.

01:23:31 Folks who have it are born with this condition and carry it throughout their entire lifetime.

01:23:36 If you really want to get rid of it, there's always hair dye available, but I personally

01:23:41 think it looks super cool.

01:23:44 We all know cilantro really isn't everyone's cup of tea.

01:23:48 I don't know about you, but it tastes like soap to me.

01:23:50 It turns out it's not actually a preference, but rather a gene that causes the plant to

01:23:55 have this vile taste instead.

01:23:58 A study performed on a group of about 30,000 people revealed that you can find a particular

01:24:03 gene variant in people who say that cilantro tastes soapy.

01:24:08 This gene has more to do with the odor of the plant than the taste itself.

01:24:12 If you're one of those people but really want to give cilantro a chance, either way,

01:24:17 there's a small trick you can try.

01:24:19 Or ask the people that cook the meals in your household.

01:24:22 You can always crush the herb before using it in dishes.

01:24:25 Why does that help?

01:24:27 Well, because with crushing, the chemicals that are responsible for the soapy taste are

01:24:31 broken down and are less likely to taste unpleasant.

01:24:36 Most people are sure that humans only have five senses, but that's not entirely true.

01:24:42 Taste, touch, smell, sight, and hearing aren't the only ones we have.

01:24:47 Scientists claim that people have between 9 and 20 senses in total.

01:24:51 These include thermoception, the sense of warmth, equilibrioception, the sense of balance.

01:24:58 There's also the sense of time, although not everyone seems to have that last one.

01:25:03 We used to think that there were just 8 different blood types, but in reality, there are over

01:25:08 30 known blood group systems.

01:25:10 Here on the Bright Side, our favorite blood group is B-positive.

01:25:14 Get it?

01:25:15 For every pound of fat you gain, you generate one mile of new blood vessels to supply oxygen

01:25:21 and nutrients to your body.

01:25:23 Your stomach produces a new lining every six days to avoid digesting itself.

01:25:29 Nerve cells transmit 1,000 nerve impulses a second.

01:25:33 They travel between 1 and 268 miles per hour.

01:25:37 Our DNA contains 100,000 viruses.

01:25:41 Scientists have discovered one that goes back 100 million years.

01:25:45 Your body emits visible light.

01:25:47 You're the brightest at 4pm, and your glow is the least visible at 10am.

01:25:52 Unfortunately, this glowing is 1,000 times less intense than what your eyes can see.

01:25:58 Sweat is mostly water mixed with proteins, sugars, ammonia, and a lot of other stuff.

01:26:04 It even contains tiny amounts of trace metals like copper, zinc, nickel, iron, and so on.

01:26:10 What makes sweat taste salty is the sodium it contains.

01:26:14 Plus, the more salt you eat, the saltier your sweat is.

01:26:18 Your body's trying to get rid of the excess, and the fastest way is to sweat it out.

01:26:23 If you walked 2 miles per hour, you'd have to walk for 20 hours straight to lose one

01:26:28 pound.

01:26:29 And it would take you 518 days and 8 hours to circle the equator.

01:26:34 Earwax isn't actually wax.

01:26:37 It contains fat, skin cells, sweat, and dirt.

01:26:41 Your brain gets three times bigger over the first year of life and reaches its full maturity

01:26:45 when you're 25.

01:26:47 60% of it is fat.

01:26:50 Your brain generates around 23 watts of electrical power, which is enough to run a small light

01:26:55 bulb.

01:26:57 Humans can't really multitask.

01:26:59 Your brain can't perform more than one action at the same time.

01:27:03 It switches between them, which doesn't save time as you might think, but increases the

01:27:08 possibility you'll do something wrong and makes the process longer.

01:27:12 When you have an exam to take or you're at work trying to focus on an important task,

01:27:17 try chewing gum.

01:27:19 Research showed it can help you stay concentrated for longer on tasks that require your full

01:27:24 attention.

01:27:25 Studies even say that it's a better test aid than caffeine.

01:27:29 There's nothing special in the gum, but the act of chewing wakes your brain up.

01:27:33 The effect doesn't last long, though, just for 20 minutes.

01:27:37 Humans develop fingerprints at 3 months.

01:27:40 Your bones are 4 times harder than concrete.

01:27:43 The strongest bone in your body is the femur.

01:27:45 It can support up to 30 times the weight of a grown-up person.

01:27:49 Even crazier is that our bones are made up of composite material, meaning they're both

01:27:54 hard and elastic at the same time.

01:27:57 Sunburn is the result of radiation exposure.

01:28:00 When your body's natural defense mechanism gets overwhelmed trying to fight UV rays,

01:28:05 a toxic reaction occurs that results in sunburn.

01:28:09 Goosebumps are an evolutionary reflex left over from our ancestors.

01:28:13 The release of adrenaline made their hair stand up, and they look scarier to approaching

01:28:17 predators.

01:28:19 Your body produces 1 to 3 pints of saliva every day.

01:28:23 It helps you digest food and fights off infections.

01:28:26 You also have a lot of bacteria in your mouth.

01:28:28 Yeah, that's right.

01:28:30 The average amount of bacteria in a person's mouth is almost the same as the number of

01:28:34 people living on Earth.

01:28:35 That's hard to digest.

01:28:37 Each human has roughly 150,000 hairs on their head.

01:28:41 Every strand grows around one-half an inch per month.

01:28:44 If we added the growth from each hair, it would measure the distance of 10 miles in

01:28:49 just one year.

01:28:50 Your hair is also a lot stronger than you think.

01:28:53 A single strand can hold 3 ounces, which is the weight of an apple.

01:28:57 If we combine the strength of all the hair on your head, it could support the weight

01:29:01 of two elephants.

01:29:02 Hey, let's try it!

01:29:05 The beating sound your heart makes is the clap of valve leaflets opening and closing.

01:29:10 Your heart doesn't replicate itself unless you have an injury.

01:29:14 Your corneas are the only part of your body that don't get blood.

01:29:17 They get oxygen directly through the air.

01:29:20 When you're sitting or standing upright, it's easier for you to recall some positive

01:29:24 memories that make you feel good.

01:29:26 Some believe it's because sitting up with your back flat boosts blood flow, and your

01:29:31 brain gets more oxygen, which helps it function better.

01:29:34 The man who has the deepest voice in the world, and that's definitely not me, can produce

01:29:39 sounds that humans, including him, can't hear at all.

01:29:44 But elephants can hear those sounds.

01:29:47 Veins look blue because light has to go through layers of skin and fat to reach them.

01:29:52 Your skin scatters a lot of the red portion of white light before it reflects the blood.

01:29:57 This leaves only the blue light to bounce back to your eyes.

01:30:01 A person who has anosmia is unable to detect smells.

01:30:05 Phantasmia is the opposite condition, when someone smells an odor that isn't actually

01:30:10 there.

01:30:11 The human brain has 100 billion neurons.

01:30:14 It's 73% water, and the same is true about the heart.

01:30:18 That's why if your brain loses even 2% of its liquid, you start to feel tired.

01:30:23 It also makes your memory worse, shortens your attention span, and puts a dampener on

01:30:28 your mood.

01:30:29 The earliest known person to have had blue eyes lived in the Stone Age, 7,000 years ago.

01:30:36 Your right kidney is probably smaller and sits lower down than your left kidney to make

01:30:40 room for your liver.

01:30:42 By the way, your brain makes sure you don't drink too little or too much water.

01:30:47 After you swallow some liquid, your mouth and throat start to fire signals to your brain,

01:30:52 telling it to stop drinking.

01:30:53 Otherwise, you'd keep gulping down water for the entire 10-60 minutes it takes the liquid

01:30:58 to get to your cells.

01:31:00 Your eyes can see something for a mere 13 milliseconds, and your brain will already

01:31:05 process this image.

01:31:07 The average blink lasts from 100 to 400 milliseconds.

01:31:12 Even though the tongue isn't the strongest muscle in your body, it never gets tired.

01:31:16 That's because of the way it's built.

01:31:18 It's made up of 8 interwoven muscles.

01:31:21 The tongue is the only muscle with ends not connected to bone.

01:31:26 Other muscles join two bones at both ends, because that's how we pull and make a motion.

01:31:31 There are around 700 different species of bacteria in your mouth.

01:31:36 Over 6 billion of them live there.

01:31:38 Your skin is your largest organ.

01:31:41 It can cover the surface area of two bath towels.

01:31:44 It accounts for around 16% of body weight and is around 22 square feet.

01:31:50 If you typed 60 words per minute for 8 hours a day, it would take you 50 years to type

01:31:55 the human genome.

01:31:57 You get tired pretty quickly when you're out in the heat.

01:32:00 This happens because your body is trying really hard to keep itself cool, which puts a lot

01:32:05 of extra work on it.

01:32:06 So, you get exhausted and tired, even if you don't do anything physically demanding.

01:32:12 Your body has 78 organs, but only 5 of them are essential for survival.

01:32:17 The brain, liver, kidney, lungs, and heart.

01:32:22 The phone's ringing.

01:32:23 It must be something urgent.

01:32:24 At 11pm.

01:32:26 Only all the gadgets in the house are silent.

01:32:29 It's your ears that are ringing.

01:32:31 You can also hear some hissing, whistling, buzzing, and even roaring.

01:32:35 But all this noise doesn't have an external source.

01:32:39 That's why it's known as phantom sounds.

01:32:42 They can occur in one or both ears, constantly or from time to time.

01:32:46 They're usually most noticeable at night, when nothing distracts you.

01:32:50 Women have more taste buds on the surface of their tongues than men do.

01:32:54 That's one of the reasons why 35% of ladies and only 15% of guys are supertasters.

01:33:01 Those are people who feel flavors more strongly than others.

01:33:04 Left-handed people usually prefer to chew on the left side, and right-handed people,

01:33:09 well, you guessed it, chew on the right.

01:33:12 Even if your fingerprints are damaged, they'll grow back in the same unique pattern.

01:33:17 When breathing, a single lung only uses 5% of the oxygen you've inhaled.

01:33:25 Now nobody really knows why we need the appendix, but it's always at the back of the book.

01:33:31 Wait, wrong appendix.

01:33:33 Some researchers claim the human appendix helped our ancestors process the tree bark

01:33:38 and whatever they were eating at that time.

01:33:40 As we have a way more balanced diet now, the appendix can disappear from our bodies without

01:33:45 any consequences.

01:33:48 Another purposeless thing in our bodies is the wisdom teeth.

01:33:51 Yeah, they used to come in handy when dentists didn't exist, but now we can ideally make

01:33:56 do without them.

01:33:58 Your brain will grow by roughly 2% if you venture into space.

01:34:02 Under normal gravity, it's thought that fluid in the brain naturally moves downwards

01:34:07 when we stand upright.

01:34:08 But there is evidence that microgravity prevents this, resulting in fluid accumulation in the

01:34:14 brain and skull.

01:34:16 When you age, your brain is gradually reducing in size.

01:34:20 By age 75, it's much smaller than at age 30, and it starts shrinking at 40.

01:34:25 It happens to everyone, so you just have to go with it and keep your brain busy and nimble.

01:34:31 If you stare into your eyes in the mirror, you'll see a small pink circle settled in

01:34:36 the corner of your eye.

01:34:38 This is your third eyelid.

01:34:39 Useless for us, but valuable for animals, like birds, to keep dust and scattered debris

01:34:44 from getting into their eyes.

01:34:46 This might sound familiar to you if you've heard of natural selection.

01:34:50 In short, natural selection keeps body parts throughout generations, but some of them are

01:34:55 harmful so they're phased out in the next generation and others that aren't staying,

01:35:00 just like the third eyelid.

01:35:02 Not only your brain shrinks as you get older, you too shrink dramatically.

01:35:06 The bones get more brittle, the backbone gets compressed.

01:35:10 It works vice versa too.

01:35:12 When you rest at night, your bones kinda relax too, so you wake up taller than when you went

01:35:17 to bed last night.

01:35:19 Our ears help us keep the balance, so hearing isn't their only duty.

01:35:24 Our vestibular system occupies the inner ear.

01:35:27 Canals in your inner ear contain fluid and tiny sensors that look somewhat like hairs,

01:35:32 helping you keep your balance.

01:35:34 As for hairs, only a few body parts aren't covered with them.

01:35:38 These are palms, the soles of the feet, and lips.

01:35:42 Hairs grow even in the belly button.

01:35:43 Their purpose is to catch lint.

01:35:45 Mine does a great job!

01:35:47 And not only lint, our belly buttons have an entire animal encyclopedia in them, with

01:35:53 a range of about 70 different bacteria.

01:35:56 Some of them can also be found in soil in Japan, and even some bacteria typical for

01:36:01 polar ice caps.

01:36:02 See, you have a whole naval expedition going on and didn't even know it!

01:36:08 Only about 43% of you is you.

01:36:10 You're over 50% tiny little creatures that mainly live in your gut and other body parts

01:36:16 without ever leaving it.

01:36:18 Still, even though your cells are fewer than microbial ones, there are, on average, about

01:36:23 100 trillion of them in you.

01:36:26 With this in mind, your genes are less than half of what you consist of.

01:36:30 If you take all the microbes dwelling within your body and count their genes, it'll be

01:36:35 anywhere from 2 to 20 million genes and their combinations.

01:36:40 If you sleep, and I recommend that you do, it doesn't mean all of your body sleeps.

01:36:45 In fact, sometimes your brain has to work even harder when you're asleep.

01:36:49 It needs to process tons of information, and reports usually take time.

01:36:55 One thing that indeed rests while you're sleeping is your nose.

01:36:58 You won't smell anything nasty in your sleep.

01:37:01 The thing is that your sense of smell deactivates at night.

01:37:04 If there's some terrible smell in your bedroom, you won't even be bothered.

01:37:09 Scientists used to believe we could distinguish around 10,000 smells.

01:37:13 Nope.

01:37:14 Recent research showed that people could indicate more than a trillion smells.

01:37:19 We also remember them better than anything else, and odors can even evoke some distant

01:37:24 memories.

01:37:25 Meanwhile, our strongest and most emotional memories are usually fake.

01:37:30 It's the way the central memory works.

01:37:32 It gives us the confidence to believe everything we remember is real, even though we should

01:37:37 be confident about fewer details.

01:37:40 You don't mind if I call you a mammal, do you?

01:37:43 Well, among us mammals, only humans can always walk on two hind limbs and keep that posture

01:37:48 for their entire lives.

01:37:50 You may want to say that kangaroos or gorillas move in the same way, but kangaroos use their

01:37:55 tail as a third leg, and gorillas use the help of their long arms to keep balance.

01:38:01 Your bones take part in metabolism too.

01:38:04 Since they mainly consist of calcium, when there's not enough of this element in your

01:38:08 blood, bones start shedding it into the bloodstream, balancing your body.

01:38:12 And vice versa, when there's too much calcium in your blood, it goes into the bones to be

01:38:17 stored for later.

01:38:19 Our height, shape of our body, and skin color depend a lot on where our ancestors used to

01:38:25 live, but we can adapt to new conditions even within our lifespan.

01:38:30 For example, if you move from the plains to the mountains, you'll eventually develop

01:38:34 more red blood cells to compensate for the lack of oxygen.

01:38:38 And naturally, if you drive from a colder climate to a hotter and sunnier one, your

01:38:43 skin will change pigmentation slightly to adapt.

01:38:47 Our lifespan is programmed within our cells.

01:38:50 They constantly renew and divide, but they have a sort of internal timer that stops at

01:38:55 some point.

01:38:56 Some cells also stop reproducing sooner than others.

01:38:59 On average, cells cease dividing when we reach the age of 100.

01:39:03 If we find a way to trick ourselves into turning off the timer, we could potentially live forever.

01:39:10 But we'd be a huge mass of wrinkles by then.

01:39:14 Body fat acts as insulation material, energy reserve, and shock absorber.

01:39:19 Your body sends the most fat into your waist region because that's where your internal

01:39:23 organs are.

01:39:24 If something happens to you, this layer of fat might as well protect those organs from

01:39:29 serious damage.

01:39:31 Your skull isn't a single bone.

01:39:33 It consists of 22 different bones, many of which are fused to protect your brain.

01:39:38 The mandible, or the lower jaw, is the only skull bone that's only attached to your

01:39:43 head with connective tissues and muscles.

01:39:46 This is what makes it so mobile – you can move it in any direction you like.

01:39:50 And the smallest bone in your whole body is inside your ear.

01:39:53 It's called the stapes, and it's no larger than a grain of rice.

01:39:58 Some of the strongest muscles in your body aren't in your arms or legs – they're

01:40:03 in your head.

01:40:04 The masseter is the primary muscle responsible for chewing, and it needs to be the strongest

01:40:09 for you to eat normally.

01:40:11 And you know those muscles that allow you to move your ears?

01:40:14 Those are temporalis, located above your temples.

01:40:17 They also help you to chew your food.

01:40:19 We've got two really fast muscles – they control the eyelids' opening.

01:40:24 In fact, they're the fastest muscles in our body.

01:40:27 Eyes are fragile and need protection.

01:40:29 So when the reflex is triggered, these muscles shut the eyes within less than a tenth of

01:40:34 a second.

01:40:36 We recognize only purple-blue, green-yellow, and yellow-red colors.

01:40:41 Everything else is a combination of these three.

01:40:43 It's impossible to calculate how many of these combinations the human eye sees, because

01:40:48 every single person has slight vision differences.

01:40:51 But it's about 1 million combinations on average.

01:40:55 Your stomach has an impressive capacity, holding up to a half a gallon of liquids – a whole

01:41:01 large bottle of Coke!

01:41:02 It's pretty hard to estimate how much hard food you can squeeze into your stomach, since

01:41:06 the food is processed with your teeth before it gets down there.

01:41:10 There's not enough room for a whole turkey, but who knows, probably a good-sized chicken

01:41:15 might fit it.

01:41:17 And hey, like my grandmother said, there's always room for ice cream!

01:41:21 Now, show me where your stomach with all that cola, chicken, and ice cream is.

01:41:26 If you're pointing at your tummy, nope, it's up there, hidden in between your ribs.

01:41:31 Your tummy is full of intestines.

01:41:34 Your body actually glows!

01:41:36 It emits a super-faint light that's at its strongest at around 3-4 PM.

01:41:42 The sad news is that this glowing is 1,000 times less intense than what your eyes can

01:41:47 see.

01:41:48 Humans are the only animals that have chins.

01:41:51 Even our closest genetic relatives, gorillas and chimps, lack this small piece of bone

01:41:56 that extends forward from the jaw.

01:41:58 Their lower jaws slant down and back from their front teeth.

01:42:02 Scientists still haven't figured out this mystery.

01:42:04 The opinions about why people are made this way differ.

01:42:08 Some researchers think chins help us chew our food.

01:42:11 Others are sure they have something to do with speaking.

01:42:14 A few of us think it's simply a special place to grow a goatee.

01:42:18 The most abundant element in the human body is oxygen at 65%, but it also contains lithium,

01:42:25 cobalt, gold, and uranium.

01:42:28 The rarest one of all is radium.

01:42:32 On average, humans yawn 20 times a day, partially spontaneously, for example, when you're tired,

01:42:38 but sometimes when someone yawns near you.

01:42:41 Scientists think it could be a thing called social mirroring.

01:42:44 Usually, when animals mimic each other, they recognize some action as useful, so they decide

01:42:50 to do it too.

01:42:51 With humans, it happens when someone crosses legs, laughs, smiles at you, or "ughhh."

01:42:59 Your stomach acid breaks down the foods you eat and turns them into easy-to-digest particles.

01:43:04 It also stops nasty pathogens and microbes that could make you sick.

01:43:09 In fact, your stomach acid is so strong that it can even dissolve bone and metal.

01:43:14 Don't start munching down on your soda cans, though.

01:43:17 That's probably not going to end well.

01:43:20 Your brain has more than 86 billion nerve cells.

01:43:23 They're all joined together by 100 trillion connections.

01:43:27 That's even more than the number of stars in the Milky Way galaxy.

01:43:31 There's a good chance you can guess someone's name based on how they look.

01:43:35 Researchers showed portrait photos to a group of people with four names written below.

01:43:40 They were asked to choose the right name for this or that person.

01:43:43 The law of chance says you'll guess it 25% of the time.

01:43:47 But in this research, people got the names correct at a rate of 25 to 40%.

01:43:53 And there were more than 94,000 faces shown.

01:43:56 Let's say a man is called Bob.

01:43:59 People will expect for him to have a rounder face than Tim.

01:44:03 They expect Bob to be more jolly and ready to hang out with people.

01:44:07 It has to affect his facial appearance in some way.

01:44:10 A woman called Catherine can be considered more serious, studious, and concentrated.

01:44:15 That could eventually influence her facial muscles as well.

01:44:19 When ancient Romans flexed their biceps, they thought their muscles looked like mice.

01:44:25 That's why the word "muscle" translates as "little mouse" in Latin.

01:44:30 Your left lung is smaller than the right one because it shares space with your heart.

01:44:36 Experts used to think that we can only distinguish 10,000 smells.

01:44:39 In fact, a recent study found human beings can recognize 1 trillion smells.

01:44:45 Millennials or people born between 1981 and 1996 are more forgetful than older people.

01:44:52 The main cause of their forgetfulness comes from higher levels of stress.

01:44:56 So come on, dude, chill out, okay?

01:44:59 Some scientists think that the purpose of fingerprints is a better grip.

01:45:03 But others believe they're there to help wick water off them and allow the skin to

01:45:07 stretch when needed to protect it from damage.

01:45:10 There's also a theory saying that fingerprints improve the sense of touch.

01:45:15 Hot coffee can taste better than cold coffee.

01:45:18 Your taste bud receptors are most sensitive when your food is at or a little bit above

01:45:22 room temperature.

01:45:24 Hot coffee can then seem less bitter because taste buds that detect bitterness are more

01:45:28 sensitive when the coffee is cold.

01:45:31 The biggest molecule in the human body is the chromosome 1.

01:45:36 A human cell has 23 chromosome pairs, and each chromosome 1 is made of 10 billion atoms.

01:45:43 You inhale 25 sextillion molecules in just one breath.

01:45:48 That's 25 followed by 21 zeros.

01:45:52 When you're walking faster, at some point, you'll feel the natural urge to start jogging.

01:45:57 Your body wants to have a stable state, whether you're running or walking.

01:46:01 So if you're walking fast, it will unconsciously force you to start running.

01:46:06 One theory is, we use more energy when walking faster than running, so that's one of the

01:46:10 ways the body saves energy.

01:46:13 Your pinky is a powerful little thing.

01:46:16 Without it, your hand would lose a significant part of its power.

01:46:20 Your index and middle fingers cooperate with your thumb to grab and pinch.

01:46:24 And your pinky, together with your ring finger, provides grip strength.

01:46:29 The fattiest organ in your body is your brain.

01:46:32 Fat makes up at least 60% of its dry weight.

01:46:35 This quality got the brain to the Guinness World Records.

01:46:39 The organ contains around 25% of your body's cholesterol, which is vital for the brain's

01:46:44 well-being.

01:46:45 Our bones are four times harder than concrete.

01:46:48 The strongest bone in your body is the femur.

01:46:51 It can support up to 30 times the weight of a grown-up person.

01:46:55 Even crazier is that our bones are made up of composite material, meaning they're both

01:47:00 hard and elastic at the same time.

01:47:03 Your fingernails grow twice as fast as your toenails.

01:47:06 It would take 15 and a half months for your toenails to grow one inch, but only seven

01:47:11 months for your fingernails to get this long.

01:47:14 The outer layer of your skin is thicker on your feet than on other parts of your body.

01:47:19 The heart has its own electrical system and can continue beating even when it's disconnected

01:47:24 from the body.

01:47:25 The vessels in your body are long enough to circle the Earth twice or more.

01:47:30 The idea that we use only 10% of our brains is a myth.

01:47:34 At any given time, you use almost 100%.

01:47:37 Otherwise, you wouldn't be able to perform simple tasks like drink a cup of coffee.

01:47:43 More than 70% of your brain consists of water, and it needs 20% of your body's oxygen supply.

01:47:50 The average lifespan of one eyebrow hair is four months.

01:47:55 The body of a 110-pound person contains 40 tablespoons of salt.

01:48:00 If you ironed out all the wrinkles in your brain and laid it flat, it would be the size

01:48:05 of a pillowcase.

01:48:07 The brain wrinkles as there's not a lot of room in the skull, so it folds over itself

01:48:11 as it grows.

01:48:12 By the way, don't do that pillowcase thing with your brain.

01:48:15 Trust me on this one.

01:48:17 We spend 40% of our life with our eyes closed.

01:48:21 Most of that time is when we're asleep.

01:48:23 But don't forget to count blinking too.

01:48:26 Or while driving.

01:48:27 You produce around 85,000 pints of spit in your lifetime.

01:48:32 That's enough saliva to fill around 500 bathtubs.

01:48:36 Nuff said.

01:48:37 The highest blood flow isn't actually in your heart, and it's not in your brain either.

01:48:42 It's in your kidneys.

01:48:44 It's super hard for us to grasp just how small an atom is.

01:48:48 But think of it this way.

01:48:49 Your body is made up of a staggering 7 octillion atoms.

01:48:53 Yeah, doesn't that look like a 7 being chased by a whole mob of zeros?

01:48:59 For adults, the blood makes up 7-8% of the total body weight.

01:49:03 About 55% of your blood is liquid plasma.

01:49:07 The rest is red and white blood cells and platelets.

01:49:10 They form clots and prevent bleeding.

01:49:13 You can't swallow and breathe at the same time.

01:49:16 The food you swallow and the air you breathe go down the same part of your throat at first.

01:49:21 Only a bit deeper does the passage split into the esophagus, for food and liquid, and the

01:49:26 trachea, for air.

01:49:28 When you swallow, your airway gets automatically closed off.

01:49:32 This prevents you from accidentally inhaling food.

01:49:36 But occasionally, it still happens.

01:49:38 There's a name for the growling sound that your stomach makes when you're hungry.

01:49:42 It's called borborygmi.

01:49:45 It takes 6-8 hours for food to travel through your stomach and small intestine.

01:49:50 That's because your body is trying to absorb all its nutrients.

01:49:54 The idea that the tongue has flavor zones is a myth.

01:49:58 All taste buds can detect 5 tastes, but some receptors are more responsive than others.

01:50:04 Human beings are the only animals that willingly delay sleep.

01:50:08 Just make sure you get enough.

01:50:11 Your dog doesn't actually have a stronger sense of smell than you do.

01:50:15 People often talk about how dogs have a superior sense of smell.

01:50:20 And this probably started when a researcher from the 19th century, Paul Broca, marked

01:50:25 humans as non-smellers.

01:50:27 No one ever provided sensory testing to support this theory, but people still believed in

01:50:32 it for a long time.

01:50:34 The truth is, different types of animals can identify different kinds of scents.

01:50:39 There was an experiment done where human volunteers needed to track a scent.

01:50:44 Researchers dipped twine in chocolate essence and then zigzagged it all across a grassy

01:50:49 field.

01:50:51 Volunteers weren't allowed to use other senses.

01:50:54 For example, they were earmuffed and blindfolded.

01:50:57 They even wore thick gloves and knee pads.

01:51:00 The conclusion they came to is that while we are not as effective as dogs, we can follow

01:51:06 a scent trail and become way better if we practice.

01:51:10 Interestingly, humans are more sensitive to certain smells compared to dogs, like fruit

01:51:16 or flowers.

01:51:18 This is because the evolution of dogs didn't require them to sharpen their sense of smell

01:51:22 for these types of odors.

01:51:24 A TV screen won't ruin your eyesight.

01:51:27 At least, there's no evidence that looking at a TV screen can really hurt your eyes.

01:51:32 It's the same for phone or computer screens.

01:51:35 Looking at them may lead to eye strain or fatigue, but in most cases, it's nothing you

01:51:40 can't ease with proper rest.

01:51:43 That doesn't mean watching TV or staring at your phone for too long doesn't have negative

01:51:48 consequences in other parts of your life, like reduced concentration and lack of socialization,

01:51:54 among many other things.

01:51:56 Being able to roll your tongue is not really a genetic trait, even though biology teachers

01:52:01 often say this "gift" is based on a dominant gene.

01:52:05 There was a study that showed 7 out of 33 twins who didn't actually share this feature.

01:52:12 Identical twins share the same genes, which implies that they should share this trait

01:52:16 too.

01:52:18 But they don't, which means genes are most likely not the factor that decides if you'll

01:52:23 be able to roll your tongue.

01:52:25 And this myth still exists, even though it was debunked over 6 decades ago.

01:52:30 "You're going to catch a cold if you go outside with wet hair" is yet another myth.

01:52:36 To actually catch a cold, we need to have a virus inside of our body.

01:52:41 Also, wet hair is not something that makes you more attractive to the various germs lurking

01:52:46 around you.

01:52:47 People mostly believe this is true because they a) heard it from their parents and b)

01:52:53 associate going outside with your hair being wet with getting sick because you're generally

01:52:58 more exposed to germs when you're outside.

01:53:02 There are no truly double-jointed people.

01:53:05 Some individuals have certain parts of their bodies that are very flexible, so they can,

01:53:09 for example, touch their chin with their elbow or bend their fingers backward.

01:53:14 We often call these people double-jointed, like the secret is in them having an extra

01:53:19 hinge somewhere.

01:53:20 Well, it's not true.

01:53:22 They have single joints, but they may have bones with oddly-shaped ends, or their connective

01:53:27 tissue may be very pliable.

01:53:31 It seems the appendix, as in the organ, is useful after all, despite its poor reputation

01:53:37 as a useless intestinal tube that pretty much goes nowhere.

01:53:41 It seems the appendix is actually a reservoir for bacteria, but a good and helpful one.

01:53:47 It stores microbes that assist our body when it's fighting certain problems and illnesses.

01:53:52 In the early stage of our life, the appendix also helped us with the process of forming

01:53:57 white blood cells, together with certain types of antibodies.

01:54:01 Hey, do you know where the stomach is?

01:54:04 Sounds easy, right?

01:54:05 But it's probably not where you think.

01:54:08 Most people believe it lurks somewhere in the area behind the belly button.

01:54:12 In reality, it's a bit higher in the abdomen, sitting on top of the rest of the gut.

01:54:17 Here's how you can find it.

01:54:19 Look for the point where your lower ribs meet in the middle.

01:54:22 Now go down approximately three finger widths, and then three to your left.

01:54:27 Now you're supposed to be right over the center of your stomach.

01:54:31 You don't have taste sections on your tongue.

01:54:34 The tongue map probably showed up at the beginning of the 20th century because scientists found

01:54:39 minute differences in how strong a taste had to be in different areas inside the human

01:54:45 mouth to actually register.

01:54:47 This study created a myth that each part of the tongue was responsible for different tastes.

01:54:53 In reality, all types of taste buds are spread across all areas of your mouth, and they can

01:54:59 detect each taste.

01:55:01 This includes umami, too, which is now accepted along with the usual four – sweet, salty,

01:55:07 bitter, and sour.

01:55:09 We don't only use 10% of our brain.

01:55:12 We use way more, even when we're sleeping.

01:55:15 Scientists tested this statement, and one of the methods they used was measuring activity

01:55:20 in the brain while a person was performing various tasks.

01:55:24 Results have shown we use most of our brain most of the time.

01:55:28 The exact percentage varies from person to person, depending on what they're doing.

01:55:32 Plus, it's not possible to monitor every single one of our brain cells.

01:55:37 There are billions of them after all, so you can't know the exact number of active ones

01:55:41 at any given time.

01:55:43 When asleep, your frontal cortex – the part responsible for, let's say, higher-level

01:55:49 thinking – and certain areas that help you sense your surroundings are still working.

01:55:54 Humans don't just have five senses – hearing, taste, touch, sight, and smell.

01:56:00 This idea originated from Aristotle, a famous Greek philosopher, who said that there was

01:56:05 a sense organ for every sense – eyes for seeing, a tongue for tasting, and so on.

01:56:11 But that was thousands of years ago, and he was missing the vestibular system, a key sense

01:56:16 organ.

01:56:17 The vestibular system is the apparatus of the inner ear that our body uses to stay in

01:56:22 balance.

01:56:24 Not every sense requires its own sense organ, just a different type of sensory receptor.

01:56:29 For example, your skin alone has four different receptors for temperature, touch, pain, and

01:56:36 proprioception.

01:56:37 Proprioception is body awareness, which means that even if you move your arm behind your

01:56:42 back, you still know it's there.

01:56:45 Something an octopus, for example, doesn't know.

01:56:48 So saying we have 33 senses could be closer to the truth, not 5.

01:56:55 These include senses of balance, temperature, thirst, and many more we need to survive.

01:57:01 If you like cracking your knuckles from time to time, no need to worry.

01:57:04 The whole idea that it increases risks for potential knuckle problems perhaps makes sense

01:57:09 in the first place because that's what happens when you constantly put pressure on your joints

01:57:14 over the years.

01:57:15 The satisfying sound you hear happens because of bubbles bursting in the fluid that actually

01:57:21 lubricates your joints, called synovial fluid.

01:57:25 If you eat a big meal, you can still go swimming.

01:57:29 You won't get cramps.

01:57:31 The idea behind this misconception is eating a heavy meal will increase the amount of blood

01:57:35 flow to your stomach.

01:57:37 That way, blood won't go to your muscles, which will potentially cause cramps if you

01:57:42 go swimming.

01:57:43 The truth is, you probably won't feel that comfortable swimming immediately after eating

01:57:48 a large meal, but you're safe to go if you really want to.

01:57:52 It's even recommended to have a small snack that's rich in carbs not long before your

01:57:56 swimming session.

01:57:57 This will boost your energy.

01:58:00 When you shave your body hair, you don't have to worry about it growing back darker and

01:58:04 thicker.

01:58:05 Because this is a myth.

01:58:07 You may believe there are some changes in the color, thickness, or growth rate of the

01:58:12 hair.

01:58:13 That's because after you shave, you give the follicle a "blunt tip," which may look or

01:58:18 feel darker and rougher than it was before.

01:58:21 But that's just a perception trick.

01:58:24 You'll see that once your hair grows in again, it will be the same as before.

01:58:29 It's a myth that we lose a disproportionate amount of body heat through our heads.

01:58:33 You may feel like that because our head, chest, and face are definitely more sensitive when

01:58:38 it comes to changes in temperature.

01:58:41 In reality, you'd be just as cold if you went out without a hat, as if you weren't wearing

01:58:46 pants.

01:58:47 You probably feel like you're losing heat through your head because it's often one of

01:58:51 those parts that we leave uncovered when going out.

01:58:55 No need to worry if you wake up a sleepwalker.

01:58:58 You're not going to seriously harm them by doing so.

01:59:01 If you startle one, they can be quite disoriented and may have a confused reaction.

01:59:07 Sometimes it's better to do that than to let a sleepwalker get up and start doing certain

01:59:11 things that they shouldn't be doing while sleeping, like cooking or driving.

01:59:16 Or you could just show them the way back to bed.

01:59:19 The cornea is the only part of your body with living cells that doesn't have blood vessels.

01:59:25 It gets nutrients and oxygen directly from the tear fluid on the outside, and the thick

01:59:31 watery substance you have between the cornea on the inside, and also from the nerve fibers

01:59:36 connected to the cornea.

01:59:39 That's why contact lenses used to be a potential issue.

01:59:42 The older ones were reducing oxygen supply, since the cornea mostly gets oxygen from the

01:59:48 outside.

01:59:49 This problem was solved, or at least reduced, when silicone hydrogel lenses came to the

01:59:54 market.

01:59:56 Some other parts of your body with no blood vessels are your nails, hair, outer skin layers,

02:00:02 and tooth enamel.

02:00:04 Did you notice your sweat sometimes smells of onions after your workout?

02:00:08 You have nothing to worry about.

02:00:10 There are two types of sweat glands in your skin.

02:00:14 The first kind of glands are located on certain areas of your body, like the groin region

02:00:19 and the armpits.

02:00:20 They produce a specific oily fluid, which is a response to certain emotional experiences.

02:00:27 Another type of sweat gland is way more common.

02:00:30 They're distributed all over your body, and are responsible for the specific sweat you

02:00:34 get after the workout.

02:00:37 The sweat cools your body down as it evaporates from your skin.

02:00:40 It's 99% water, so it's practically odorless.

02:00:44 Well, at least when it first leaves the pores and comes to the surface of your skin.

02:00:50 But there are many types of bacteria on the human skin, and they feed on the nutrients

02:00:54 in that sweat, together with skin flakes.

02:00:58 One of the byproducts of this is specific chemicals, and their smell can sometimes strongly

02:01:02 remind you of onion.

02:01:05 You may have noticed you produce more saliva when you go for a run, especially if it's

02:01:10 a short jog in cold weather.

02:01:13 But if you're running a marathon, and it's a nice warm day outside, you'll produce less

02:01:18 saliva.

02:01:19 It's your body trying to offset the drying effect, since you breathe through your mouth

02:01:24 way more.

02:01:27 But your body becomes more dehydrated over longer periods, which is why it's trying

02:01:32 to conserve water by reducing saliva production.

02:01:35 Every training you do, no matter how intensive it is, also makes you secrete more of a specific

02:01:41 type of protein.

02:01:43 It makes the saliva more viscous and sticky, which is why you may feel like your mouth

02:01:48 is dry way more after your workout.

02:01:52 Humans see the world 15 seconds out of date, which means your brain constantly keeps you

02:01:57 a little bit in the past.

02:02:00 This way, it helps you stabilize your vision of the world around you.

02:02:04 Your eyes receive a huge amount of visual information.

02:02:07 Yep, literally millions of colors, shapes, and ever-changing motion wherever you turn.

02:02:14 It's not an easy task for your brain to process all that.

02:02:17 The visual world alters all the time because of changes in viewpoint, light, and the rest

02:02:22 of the outer factors.

02:02:25 Your visual input changes because you need to blink.

02:02:28 Plus, your head, eyes, and your entire body are always in some sort of motion.

02:02:35 Your brain has to establish a mechanism that can create illusory stability.

02:02:40 It automatically smooths your visual input.

02:02:42 It doesn't analyze every little visual snapshot.

02:02:46 It's like a time machine.

02:02:48 You actually perceive an average of things you saw in the past 15 seconds at any given

02:02:53 moment.

02:02:55 The brain pulls together objects so they appear more similar to each other.

02:02:59 That's why it tricks you into believing you're in stable surroundings.

02:03:03 If your brain kept you updated in real time, the world would feel like a very, very chaotic

02:03:08 place with constant changes in movement, light, and shadow, which would probably feel like

02:03:14 you were hallucinating all the time.

02:03:18 Your bones are really strong, but your teeth, which we also consider as part of the skeletal

02:03:23 system, are even stronger.

02:03:26 That's because of the enamel, the hard outer layer of your tooth.

02:03:30 The enamel keeps the tissue and the delicate nerves inside your teeth safe.

02:03:36 You're basically burning calories while you're thinking.

02:03:39 When you rest and don't engage in any particular activity, except for the basics, which includes

02:03:44 digesting, breathing, and keeping yourself warm, it's the stage where your brain uses

02:03:50 up to 20-25% of the total energy of your body.

02:03:54 That means your body will burn around 350-450 calories per day while pretty much doing nothing.

02:04:02 We're not the only ones in the animal kingdom with such a mechanism.

02:04:06 Some small mammals like the minuscule pygmy marmoset and the tiny tree shrew devote the

02:04:12 same percentage of their total body energy to their brain.

02:04:17 Most of the energy the brain burns is to help its cells, the neurons, to communicate with

02:04:21 each other.

02:04:22 They do it via chemical signals the brain transmits across synapses, those special cell

02:04:28 structures.

02:04:29 So, the brain directs a lot of energy towards synapses in order to make them work.

02:04:34 Your brain never really rests.

02:04:37 Even when you're sleeping, certain parts are active.

02:04:40 So, your brain needs its fuel to work, and you're basically burning calories in your

02:04:45 sleep.

02:04:47 The more demanding mental tasks you take throughout the day, the more calories you burn.

02:04:52 So, if you skipped today's workout, solve some Sudoku!

02:04:57 Do you like to rush with your ice cream?

02:05:00 Sometimes it pays off, but if you do it often, you must know the feeling of brain freeze

02:05:04 pretty well.

02:05:07 It's a pretty intense and uncomfortable feeling that comes from the front or sides of your

02:05:11 head right after you drink or eat something cold, such as a slushy drink, ice cream, or

02:05:17 an ice pop.

02:05:19 Some people even go through a similar sensation whenever they're exposed to cold air.

02:05:25 Scientists are still not sure exactly why this happens, but one of the theories is the

02:05:29 cold substance stimulates a cluster of nerves located at the back of the palate.

02:05:35 Another theory says the blood vessels in the roof of the mouth and sinuses quickly constrict

02:05:40 because the temperature in your mouth drops before they dilate again.

02:05:45 Brain freeze is not something dangerous that you should be seriously worried about, and

02:05:49 no, hanging over the table, groaning, or clasping your head in your hands won't help much.

02:05:57 Some people like to sleep a lot.

02:05:59 Hey, guilty as charged!

02:06:02 But some have a certain condition called familiar natural short sleepers, which means they're

02:06:07 kind of immune to sleep deprivation.

02:06:10 About 1% of our population has it.

02:06:13 They can fall short on sleep and feel pretty good about it.

02:06:17 They're fine with sleeping for 6 hours per night.

02:06:20 This amount would wreck the majority of people after a couple of nights.

02:06:24 The human eye normally has three cones.

02:06:27 That means we can recognize approximately a million different shades in the green, red,

02:06:32 and blue spectrums of colors.

02:06:35 But there are some people with a rare condition, so-called tetrachromats, that have four cones

02:06:40 in their eyes.

02:06:41 This allows them to see ultraviolet shades, which means they can distinguish 100 million

02:06:47 distinct colors.

02:06:50 Did you know your skeleton is all wet?

02:06:52 I mean, your entire body mostly consists of water, up to 60%.

02:06:57 That fluid is not only in your organs, muscles, and skin.

02:07:00 It's in your skeleton, too.

02:07:03 Your bone mass is almost one-third water.

02:07:07 There's this amazing hidden network a human body holds inside.

02:07:11 Blood vessels are really small, but if you could line them all up, you'd get something

02:07:15 huge.

02:07:16 Your entire body boasts a network of 60,000 miles of blood vessels.

02:07:22 One of the ways to keep your network healthy is by eating right.

02:07:26 Have you ever wondered why our distant relatives, the primates, are so much stronger than us?

02:07:32 In many ways, our bodies are very similar.

02:07:35 Look at the chimp's muscle structure, for example.

02:07:38 But our closest primate relatives are approximately 1.35 times stronger than us.

02:07:44 The human body developed more slow-twitch muscle fibers compared to the rest of the

02:07:48 primates.

02:07:50 This type of muscle fiber is a less powerful one, but it lets us endure more than other

02:07:55 primates, and do things like foraging and hunting, activities that helped our distant

02:08:00 ancestors to survive.

02:08:02 That's also the reason why we can run a marathon.

02:08:05 A monkey could never do it.

02:08:07 But we'd still lose in a strength competition.

02:08:11 Laughter is contagious.

02:08:13 It's not just a metaphor.

02:08:16 Researchers have found that strong emotions can make the brain activity of different people

02:08:19 sink.

02:08:22 Laughter is something science usually links with social creatures.

02:08:26 People are almost 30 times more likely to laugh when in some social situations, hanging

02:08:30 out with their friends or people they feel relaxed with.

02:08:34 One of the theories says that you're probably going to join when you see your friend laughing

02:08:38 because humans are empathetic beings.

02:08:41 Your brain will release endorphins when you're laughing.

02:08:44 These are special chemicals that make you feel safe and at ease.

02:08:47 So, we're not sure why exactly our laughter is contagious, but it feels really good, so

02:08:53 … join us on the Bright Side of life and laugh away!

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