Category
🐳
AnimalsTranscript
00:00 Have you ever wondered how animals see the world around us?
00:03 Each species or being living on our planet is unique,
00:06 its vision is also unique, and each animal perceives the colors in a different way,
00:10 sometimes with colors that humans have never seen.
00:14 Welcome to "How animals see the world".
00:17 Dogs.
00:24 You are currently seeing two very distinct images.
00:27 The left one represents how we see the world, and the right one represents what a dog perceives.
00:32 And yes, contrary to what we thought until not so long ago,
00:35 the dog does not see in black and white, but it is true that its spectrum of vision is much narrower than ours.
00:40 Basically, it is limited to two complementary colors, yellow and blue,
00:45 for a result that is closer to a monochromatic vision than a colored vision.
00:49 Dogs, on the other hand, are very sensitive to movement and to the difference of humans who have a field of vision of 180 degrees.
00:56 Dogs, on the other hand, have a field of vision of 240 degrees.
01:00 Cats.
01:03 If dogs and cats are known to not get along and to fight all the time,
01:07 the two species have an incredible point in common that is none other than their vision.
01:13 Cats perceive practically the same colors as dogs, that is to say green, blue and yellow.
01:18 Reduced to only a few colors, they are therefore obliged to focus on the movement of their prey.
01:24 In addition, the vision of cats is not good during the day because their eyes absorb 8 times more light than humans.
01:29 Cats therefore suffer from a very poor perception of colors in the morning,
01:33 and that is why they are much more active at night.
01:36 Birds.
01:38 Birds have a unique ability that allows them to see better than all other animals, or almost.
01:44 Thanks to their four photoreceptors, they can perceive colors that we have never seen,
01:48 because we only have three photoreceptors.
01:51 This photoreceptor also gives birds the ability to see not only the light of day, but also the ultraviolet light.
01:58 They are also able to detect urine traces left by their prey,
02:02 spots and colors in the feathers of other birds,
02:04 and many other little things that are absolutely not visible to our human eye.
02:08 Cats and mice.
02:11 The vision in rodents like cats and mice is limited,
02:14 since they use more of their odor or their touch.
02:17 They have a dichromatic vision, which means that they only perceive two colors, which are green and blue.
02:23 Other colors are perceived in a grayish tone.
02:26 But don't think that's all that disables them.
02:28 The eyes of rats are extremely small, thus preventing them from seeing clearly at great distances.
02:33 But since they are placed on both sides of their heads, it gives them a very wide field of vision,
02:38 and in addition, rats can close their eyes separately and independently from each other.
02:42 A very useful skill when monitoring a predator.
02:47 Snakes.
02:48 Unfortunately, the vision of snakes is not as developed as that of other species.
02:53 Since most species of snakes spend their time stuck to the ground,
02:57 their vision is therefore conditioned by the very low altitude of their body.
03:01 They really distinguish very few colors compared to human vision.
03:05 In fact, we could almost say that the snake sees in black and white,
03:08 so the colors it perceives are opaque and dark.
03:11 To compensate for this, snakes are equipped with infrared receptors near their nasal folds.
03:16 These receptors, combined with the signals of their eyes, allow them to perceive the body heat of their prey.
03:21 At nightfall, all prey become bright for snakes,
03:25 which allows them to capture them much more easily.
03:28 Fish.
03:30 The vision of fish resembles that of humans, but with a spherical lens.
03:35 These aquatic animals are able to distinguish colors and ultraviolet lights.
03:39 Their eyes are on the sides of the head.
03:41 This gives them a very ample field of vision and they are able to see almost everything around them.
03:46 Unlike our eyes, fish eyes are trained to see very well underwater and very clearly in the dark.
03:53 Flies.
03:55 There are many myths about the vision of flies.
03:58 At first, it was believed that since they had many facets on their eyes,
04:02 their vision would consist of grouping several repeated images on several planes.
04:06 But researchers quickly realized that they were wrong.
04:09 The most impressive thing about flies is their reaction time.
04:12 Have you ever tried to kill a fly?
04:14 It's damn hard, isn't it?
04:16 It looks like it already knows when to hit it.
04:18 Have you ever wondered why?
04:20 What really happens is that a fly perceives time in a different way from us.
04:24 Flies perceive 200 images per second, when a human being perceives only 24.
04:29 So when a predator approaches a fly,
04:32 the insect is able to break down its movement thanks to its eyes,
04:35 which work like a very slow camera and which gives it time to react.
04:39 Horses.
04:41 Most people have three kinds of cones that allow them to see a wide range of colors.
04:47 Horses have only two types of cones,
04:49 so they probably see the world with much less colors than us.
04:53 They can easily distinguish red or blue from gray,
04:56 but find it much more difficult to distinguish green from yellow.
04:59 Another peculiarity, the eyes of the horse are on both sides of his head
05:03 and not on the face like the human being.
05:05 Being separated from each other, each eye transmits to the horse a different vision of the world.
05:10 Except when the horse looks in front of him.
05:12 In this case, the animal perceives the same thing on both sides.
05:16 The longus.
05:19 And finally, we have one of the strangest visions of the planet,
05:22 which is still a mystery to humanity today.
05:26 As we saw earlier, we human beings have three types of photoreceptors.
05:31 Birds have four, and some species of butterflies have five.
05:35 Well, a longus has twelve!
05:38 Yes, twelve!
05:40 It can detect visible light, ultraviolet light and polarized light.
05:44 And it can also move each eye independently.
05:48 How a longus sees the world, this remains a mystery.
05:51 We believe that the vision of the longus can be something that looks like the fluorescent image
05:55 that you see right now on the screen, but we don't know more.
05:58 I hope you enjoyed this video.
06:01 If so, don't hesitate to give us your opinion in the comments and to subscribe if you haven't already.
06:06 See you soon for a new video!
06:08 [Music]