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00:00The Jura mountains on the French-Swiss border are in the grip of winter.
00:09The ground has been frozen solid for months.
00:12This is a tough place in which to live.
00:17I'm told that clearings like these could be the home of a real giant.
00:23At this time of the year, it'll be in hiding.
00:30But evidence of its existence, these strange mounds, is everywhere.
00:38Inside here, deep down and protected from the cold, the giant is asleep.
00:47Beneath the thatch of spruce needles lies a maze of tunnels and chambers
00:53the home of hibernating wood ants.
00:56Individually, they're tiny, but they're members of a giant supercolony.
01:04When temperatures rise, over half a billion of them will emerge and dominate this landscape.
01:15Scientists are only just working out how ants manage to survive up here.
01:21But in fact, there's a much greater and more profound mystery that has brought me up this mountain.
01:29Among ants, cooperation between colonies is very rare.
01:34Warfare is common.
01:37Yet these nests over a great area live at peace with one another.
01:46This may sound like an epic tale of war and peace.
01:50But does it also contain an echo of human nature?
01:57These ants, in some extraordinary way, have exchanged war for peace.
02:02It's now recognized as one of the largest of all insect super societies.
02:08And its very existence conflicts with some of the laws of evolution as we presently understand them.
02:21It's been a long, cold winter here in the Swiss Jura mountains.
02:33It's hard to believe that any insect could survive in this frozen landscape.
02:39But now, change is in the air.
02:43Soon, ant nests all over this mountain will come to life.
02:49Some of these mounds are independent colonies.
02:52But others are part of one huge super colony.
02:57Over the coming months, I'll be looking at the differences between these two wood ant societies.
03:04One that wages war with all its neighbors.
03:07And the other which welcomes them and lives at peace.
03:21As the grip of winter eases, sentries emerge from the mounds to check on conditions.
03:28They detect the sign that they've been waiting for.
03:32The temperatures are rising.
03:36Spring is on the way.
03:39The ants survive the winter thanks to their own central heating system.
03:44Warmth given off by the slow decomposition of the dead vegetation in the nests.
03:52And the ants' ability to survive the cold winter.
03:56The ants survive the winter thanks to their own central heating system.
04:02Warmth given off by the slow decomposition of the dead vegetation in the nest's fabric.
04:09And that prevents them all from freezing.
04:15Now, by swarming all over the surface of the nest, they're recharging their batteries.
04:21Absorbing heat directly from the sun's rays.
04:26The ants' ability to survive the cold winter.
04:38This behavior only happens over one or two days in the early spring.
04:44The worker ants have emerged into the sunshine and are now clumping together.
04:50And they're not just sunbathing.
04:53It could well be that the ultraviolet rays of the sun cure them of any infections from viruses or fungi
05:00that may have happened during their long sleep underground.
05:08You can almost feel the enthusiasm with which these little creatures are enjoying their sunbathe.
05:24This is unusual enough, but now here is something truly extraordinary.
05:30There is a queen.
05:35She's almost twice the size of her subjects.
05:40She's also the most important member of her family.
05:44And what's more, there's another.
05:47To see a queen exposed and vulnerable outside the nest is very rare indeed.
05:59And there's another.
06:01Shining wonderfully in the sunshine.
06:05A normal wood ant nest usually has just a single queen who lays all the eggs.
06:11But clearly, this is not so here.
06:16There's another. There's another. Several of them.
06:20Amazing.
06:31After a few moments in the sunshine, the only time they see daylight in the whole year,
06:36the queens disappear and make their way back to the brood chambers deep in the nest.
06:47Those unwilling to go are dragged back.
06:50We may call them queens, but there's no sovereign rule here.
06:54The workers govern by consensus and they decide when and where the queens will go.
07:09There may be hundreds of queens in this single nest.
07:12There may be hundreds of queens in this single nest.
07:16And there are over a thousand such mounds as this, all interconnected.
07:23So, across the supercolony, there may be as many as a million queens.
07:37It's now early April.
07:40The queens return below to prepare for the egg laying, started a race against the clock.
07:46They must complete their most important work below in the next two months.
07:56Using infrared light, which is invisible to the ants,
08:00we can watch them inside their nest without disturbing them.
08:10Most of the first eggs to be laid will produce the next generation of breeding individuals,
08:16the queens and the males, both of whom will have wings.
08:23Inside the thousand nests of the supercolony,
08:26over a half a billion mostly unrelated worker ants cooperate to ensure
08:32that the queens and the males will be ready for their mating flights in mid-June.
08:40FOOD
08:45With all these developments on the way,
08:47it's imperative that the workers collect more food as soon as possible.
08:54But many of the mounds are still surrounded by snow.
08:59So, the workers can't reach their feeding grounds.
09:04HEAT
09:08But there is something they can collect.
09:11Heat.
09:15The nest needs more heat than that which comes from the rotting vegetation,
09:21if the eggs are to hatch in time for their June appointment.
09:26WARMTH
09:29Now, however, the ants have another source of warmth.
09:40Using their bodies as solar panels, the ants harvest the sunlight.
09:48We have a heat-sensitive camera that detects differences in temperature.
09:53The nest appears black because it's hotter than the surrounding environment.
10:02It shows a similar difference in the ants.
10:08Those going down into the nest are black because they've been heated by the sun,
10:13whereas those coming out are white because they're cold,
10:17having transferred their body heat to their charges in the brood chambers below.
10:23HEAT
10:27It's this kind of selfless collaboration that is the key to success of any ant colony.
10:40In normal ant colonies, all the workers are related to one another and to the queen.
10:47And the theory is that that is why they all cooperate.
10:51But that is not the case here.
10:55There are hundreds of queens here. Over a thousand have been counted in a single nest.
11:00So all the workers can't have the same parents, and genetics have confirmed that this is so.
11:08It's this cooperation between unrelated ants in a single colony
11:12that appears to be rewriting the rules of insect evolution.
11:16But we still don't really know how this has come about.
11:20SPRING
11:26Spring is now well on the way.
11:32The snow has disappeared, and colour comes to the meadows.
11:50By late April, there are piles of eggs in the nest, and the first larvae are hatching.
12:03The workers labour unceasingly to ensure that the growing brood will be ready to emerge in six weeks' time,
12:11at the peak of the short Jura summer.
12:19SPRING
12:30But not every ant nest on this mountain can be so focused.
12:34Some will soon have to deal with threats to their very survival.
12:41Just a short distance away, on the borders of the supercolony's woodland territory,
12:46there are other wood ants.
12:50The mounds here, on this side of the mountain, look exactly the same as those of the supercolony,
12:58and so do the ants themselves.
13:04The inhabitants of each nest here are all the offspring of its single queen,
13:10and the colonies compete aggressively with one another.
13:20After the winter hibernation, the territories between that nest over there and this one here have become blurred,
13:29and the frontier has to be re-established.
13:33And in order to do that, workers from both nests are now scouring the ground,
13:39and that brings neighbouring ants into contact for the first time this season.
13:50When foragers from the different nests meet, they immediately recognise that they're from rival families.
13:59They then dash back to their nests, and within minutes, both colonies know that territory on their frontier is being disputed.
14:10Armies assemble.
14:19Armies assemble.
14:35This is war, and the weapons being used are chemical.
14:40Formic acid.
14:42I can smell it in the air.
14:44They're squirting it from the ends of their abdomen.
14:49And if they can bite their opponents so that the formic acid gets beneath the outer shell of an ant,
14:57it will dissolve its internal organs.
15:07As they grapple, each tries to restrain its opponent by clamping its jaws around a leg or an antenna.
15:19Soldiers from both sides tug at their opponent's limbs.
15:34It can take seven ants to subdue a single enemy.
15:39One holds each leg, and the seventh uses its mandibles to cut open sections of their opponent's exoskeleton, exposing the insides.
15:52An attacker brings forward its abdomen under its body and squirts acid onto its victim.
15:58Battles are going on everywhere.
16:07Each colony carries its own chemical badge, invisible to our eyes but clear to the ant's sensitive antennae.
16:15Fighters touch each other to confirm whose side they're on.
16:20Here and there, individuals clamber up the vegetation.
16:28Are they having a rest, or are they surveying progress to see where help is needed?
16:35The ants are still clinging to the ground.
16:38They're clambering up the vegetation…
16:44Are they having a rest, or are they surveying progress to see where help is needed?
16:49The smell of formic acid reaches the colony and more ants from both sides run to join
17:11the battle.
17:29These wars can continue for over a week.
17:32At their peak, many thousands are fighting and thousands are killed.
17:59The victors will certainly have enlarged their territory, but some say they have also
18:06gained other rewards.
18:08They're taking off the bodies of their victims and carrying them back to the nest over there
18:16to feast upon them.
18:26Both sides have suffered heavy losses.
18:34For the ants in the meadow, it has been a costly start to the year.
18:49Higher up the mountain, in the territory of the supercolony, the inhabitants of different
18:53nests are also meeting.
18:56But here, things are very different.
19:01These ants come from a mound about half a mile away.
19:06If that mound was a separate, independent colony, then these, when they land there,
19:14will be savagely attacked.
19:16But let's see what happens.
19:31At first, the resident ant makes an aggressive gesture, but then the other strokes the first
19:44xantenae.
19:45That gesture is a request for food, and the other obligingly feeds her.
19:55This behavior, known as trophallaxis, is in itself not unusual.
20:00Most ants do it at times.
20:02What is unique is that these ants are almost certainly unrelated, yet they treat each other
20:08as if they were from the same nest.
20:13They do this because they share the supercolony scent, a chemical signature that is transferred
20:20together with the food.
20:28In one experiment, scientists fed a distinctive chemical to a nest on one side of the supercolony,
20:35and eight weeks later, that same chemical appeared far away on the other side.
20:46It's this sharing of food between over half a billion individuals that makes this supersociety
20:53so truly remarkable.
21:05Because of this, supercolony ants can move freely between mounds, and they have as a
21:10result created over a hundred kilometers of trails that link over a thousand nests.
21:22These trails not only allow the ants to make new nests deep in the forest, they also give
21:27all the members of the supercolony access to resources of great value to them.
21:38It comes from the spruce trees.
21:59The ants don't feed directly on the spruce trees.
22:04They become farmers, and these are their flocks, aphids.
22:12The presence of the ants keeps insect predators at bay so the aphids can feed unmolested.
22:20They drink the tree's sap and excrete what they don't need as a sugary liquid called
22:26honeydew, and the ants love it.
22:39Just as human farmers milk their cows, so the ants stroke the aphids with their antennae
22:45to persuade them to release their honeydew.
22:58Once the aphids are milked, and the ants have drunk as much honeydew as they can carry,
23:04they head down the tree, abdomens bulging, and return to the nest.
23:17The honeydew is not only food with which to sustain themselves.
23:22Some use it to raise the heat of their bodies well above normal and so warm the atmosphere
23:27within the nest, a valuable ability in the fickle climate of the Jura.
23:34The spruce trees themselves also produce a substance that the ants can use directly.
23:45These ants have collected little flakes of resin.
23:51That's a sort of gum that oozes from the broken twig of a coniferous tree.
23:57The tree uses it to seal off an injury, but what are the ants using it for?
24:07Inside the nest, the extra warmth produced by honeydew helps the queens to keep laying,
24:14and the larvae to keep growing.
24:20However, constant warmth can create problems.
24:26Despite regular cleaning, diseases can thrive.
24:33The ants have a remarkable solution to that problem.
24:42They cover the surface of the mounds with tiny nuggets of resin, and also take it into
24:48the chambers below.
24:50One nest contained over four kilos of it.
24:55It is, in fact, ant medicine.
25:00The ants combine acid from their bodies with the resin, and so produce a very effective
25:06antibiotic.
25:08This is one of the most sophisticated animal pharmacologies known to science.
25:16It's been shown that wood ants living in nests that contain resin are better able to
25:22survive diseases than those that don't, and their eggs are far less likely to be infected
25:28by fungi.
25:36This immense, peaceful supercolony has few enemies, but now, at the end of May, a new
25:43threat has arrived.
25:56The Jura is famous for producing some of Europe's finest cheese.
26:06For generations, farmers have made small clearings in the woods to create meadows where cattle
26:11can graze.
26:18Only now is it warm enough for cows to be brought up to these high pastures.
26:26Somehow, the ants need to make sure that they're left alone, and that nothing damages their
26:36nests.
26:39And that's a considerable challenge, even for a supercolony.
26:55But these ants are very determined.
26:57When one squirts its acid, others follow suit.
27:10The result is a coordinated barrage.
27:25The cows are not harmed, but they do get a dose of acid in the nose, which they don't
27:30like, and they tend thereafter to avoid these mounds.
27:55By now, in June, the larvae have become big and greedy.
28:00They must be given special care, because they will produce the next generation of royalty,
28:06so the workers labour hard to meet their demands.
28:10In summer, hundreds of thousands of eggs are hatching every day, and honeydew is not enough.
28:19The ants go in search of something else, a supplement, fresh meat.
28:29The lush green hills and mountains of the Jura are now teeming with all sorts of life,
28:35and nearly all of it is potential food.
28:58The ants spread out from the nest, scouring every square inch of the ground in search
29:03of prey.
29:15As the hunters approach, those that can take flight.
29:32The ants' vision is not very acute.
29:34They can only see a target if it moves.
29:42A wolf spider, however, can see the ants clearly.
29:46But as long as she doesn't move, they won't know that she's here.
30:02She's carrying a little sack full of eggs.
30:22She decides to run for it, and her sudden movement alerts the hunters.
30:47That first fleeting touch by an ant left a faint scent mark, and now fellow hunters
30:53can home in on their target.
31:00The spider has a venomous bite, but that is no use now.
31:04Eight powerful legs are her only hope, but her speed is the very thing that enables the
31:09ants to follow her.
31:18Slow motion reveals the basic ant hunting technique.
31:22Lunge with jaws open, and hope for the best.
31:40At last, an ant manages to grab her.
31:46Like a pride of lions taking down a buffalo, the ants surround her.
31:51Two restrain their catch, while another delivers the fresh dissolving acid.
32:11The wolf spider is just one of many victims.
32:26Alone an ant can take only the smallest prey, but by working as a team, they can capture
32:33creatures many times their size.
32:53A super colony can make hundreds of millions of kills every year.
33:00Beetles, caterpillars, worms, flies, they will tackle almost any living thing.
33:28Whatever the prey, it's first cut up and eaten by the workers, who then regurgitate
33:33it to feed to the larvae.
33:46Once they have grown to full size, the larvae spin silk cocoons for themselves.
34:00Inside each, a featureless larva is changing into an adult.
34:06The time in the sun is approaching.
34:26Wood ants live in one of the most highly organized and complex of insect societies.
34:33They fight wars over territory, they hunt in packs, and farm other species.
34:39They build complex homes with central heating.
34:42They produce their own medicine.
34:45And one group of them, we now know, has made another advance.
34:50The super colony has extended this collaboration beyond the frontiers of the family to form
34:57a super society of such dimensions that we can perhaps begin to compare it with that
35:03other great social creature on this planet, ourselves.
35:09People studying the origins of human culture suggest that shared myths were one of the
35:15factors that bound early human societies together.
35:19But what about ants?
35:21Well in many species, it is certainly the case that all the individuals are very closely
35:27related to one another.
35:30But that is not so in the super colony.
35:34And in some days in June, such colonies continue to break the rules.
35:46As midsummer approaches, the Jura briefly becomes a paradise of wildflowers.
35:57And something new appears inside each of the nests, wings.
36:07The royal generation, male and female, has finally hatched and both will be able to fly.
36:17Winged individuals are the only ones that are capable of breeding.
36:22The males are little more than animated insemination devices and they will soon achieve their purpose
36:27and die.
36:28But the females, which are emerging just now, this is the beginning of a long life of servitude.
36:37When the weather is just right, sunny and not too windy, the nests suddenly become covered
36:51with winged ants.
36:53There's an excitement in the air.
37:07The males, which have matte black bodies, are incapable of feeding themselves.
37:13So once they leave the nest, they only have a short time to live.
37:16There's no time to waste.
37:21The virgin queens, who are also black but splendidly shiny, have a rather clumsy beginning
37:27to their lives.
37:30They're heavy with fat reserves and swollen ovaries.
37:36So that getting airborne is not easy for them.
37:42This is the most important flight of their lives, but it's also their first.
37:50Many test their wings before take-off.
37:56They may need several attempts before they achieve complete flight control.
38:15After a few days, half a million winged ants of both sexes take to the air and head off
38:21for new territory.
38:40They then all assemble here in the heart of the supercolony.
38:47It's not clear how they find this meadow, but year after year, virgin males and females
38:55from across the supercolony are drawn here for their nuptial flight.
39:15The queens congregate in small patches of taller plants and begin to release sex pheromones,
39:22and chemicals that attract males.
39:36Detecting this scent on the wind, the males home in on the females.
39:53The virgin queens may only get the chance to mate once, and they need to obtain enough
39:59sperm to fertilize the eggs they will be producing for years to come.
40:07But with plenty of males in the meadow, they can afford to be choosy.
40:15The males are so driven, they even try to mate with females who are already doing so.
40:40These males, fortunate enough to couple quickly, make the most of their few remaining hours
40:45of life.
40:51Once they've mated, their service to the colony is over, and they die of exhaustion.
41:08The queens now have no further use for their wings, and they try to get rid of them.
41:17But they are, necessarily, rather firmly fixed.
41:29Trying to remove a backpack with your feet, even if you have six of them, is clearly a
41:34frustrating process.
42:02Eventually, the meadow is marked with little drifts of discarded wings.
42:13Such breeding swarms are fairly typical of ants, generally.
42:17But now, the queens of the supercolony do something much less common.
42:28To understand why they behave so differently, we must first return to the spring battlefields
42:33of the ordinary wood ants outside the empire of the supercolony.
42:45The warring colonies on this side of the mountain have now accepted their frontiers, and summer
42:51brings a brief pause in their battles.
42:56The mating system they use may seem, at first sight, to be the same as that of the supercolony,
43:03but in fact, it's fundamentally different.
43:06Every decision taken by a mated female is fraught with danger.
43:18The colony this queen comes from is at war with all its neighbours.
43:23So if she meets any of them, they will try to kill her.
43:27She needs a home, but she can't build it without help.
43:34Her solution to the problem is extraordinary and radical.
43:47Under this rock, a different species, field ants, have built a nest.
43:56These small ants, less than a third of her size, are common and live in meadows on the
44:01edge of the forest.
44:05The only way this wood ant queen can get her own nest is by taking over one of theirs.
44:16She will become a parasitic queen.
44:22She lurks near the nest, trying to pick up the scent of the field ants.
44:29She avoids groups of them because they could overpower her.
44:33Instead, she tackles individuals.
44:37There's a brief duel, and then she retreats.
44:43But each time, she's left with a trace of their scent, so that she slowly begins to
44:48build up a chemical disguise.
44:54These contests go on for several days.
44:58Gradually, her disguise becomes more and more convincing.
45:13The entrance to the field ant's nest is unguarded.
45:18Cautiously, she enters.
45:27Inside, she is vastly outnumbered.
45:32Wood ant behavior inside a field ant nest has never been observed in detail before,
45:37let alone filmed.
45:38So what happens next must be interpreted with caution.
45:53There are fights, and most wood ant queens are in fact killed at this stage.
46:03But after she has endured repeated attacks, some of the field ants become less aggressive
46:08towards her.
46:11Eventually, a confused field ant worker feeds the wood ant queen.
46:19And when it does that, the fate of the nest is sealed.
46:26The wood ant queen has now acquired the colony's scent.
46:30She oozes queenly pheromones, and the field ants seem entranced by their new foreign queen.
46:40The gamble has paid off, and she has a fully functioning nest ready to receive her first
46:46batch of eggs.
46:54Taking over a nest of field ants is the way typical wood ants start a new family.
47:02But how about the queens from a supercolony with their multifamily conminal nests?
47:07Have they found a more peaceful strategy?
47:12Each mated female has to set out on her own journey.
47:17If she is to become a true queen, she has to find a nest that will accept her.
47:22And that is where the tolerance of the members of the supercolony is tested once again.
47:31Being already in the heart of a supercolony, these newly mated queens don't have to walk
47:36far before encountering their own kind.
47:44But even for a supercolony queen, walking straight up to a busy trail is risky.
47:50If the workers she meets are not in a welcoming mood, they will tear her to pieces.
48:19Slowly, one by one, workers come to investigate her.
48:30Some seem uncertain whether to attack or not, but others lick and clean her.
48:47After a few tense moments, a worker starts to drag her towards the nest.
48:55This is a sign that she will be adopted.
49:04And now scientists have made a further discovery.
49:08Many nests in the supercolony shortcut the whole process.
49:14The winged males and the queen ants don't even bother to leave the nest.
49:20Many different families live here, so there's no need to fly away to avoid inbreeding.
49:31The winged queens can simply mate with one of the males that hatched here.
49:38Perhaps this unusual behavior is the next stage in the evolution of the supercolony.
49:51With these innovative mating systems, the supercolony queens don't take the same risks
49:58as normal wood ant queens.
50:00They don't need to infiltrate the nest of field ants to start a family.
50:07The workers just build new nests when needed, enabling the supercolony to extend deep into
50:13the forest where there are no field ants.
50:19It's changes in behavior like this that most likely gave rise to the supercolony in the
50:24first place and colonized this new habitat with all its riches.
50:35It's possible that this kind of cooperation between different nests is becoming more common
50:40among ants.
50:42New supercolonies are still being discovered in different species across the world.
50:48Are we perhaps witnessing the next stage of the social conquest of the earth?
50:57The supercolony consists of literally thousands of different families, all working in cooperation.
51:06It's a development that mankind achieved a very long time ago and could be seen as one
51:11of the reasons why we have come to dominate so many parts of the planet.
51:17Could it be that peace is the winning strategy on this ant mountain too?