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03:47Suitable stretches of water, secluded with plenty of vegetation around to eat, are few.
03:53And this loch will soon be crowded.
03:57Some of the arrivals are young birds travelling by themselves who have yet to find a mate.
04:07The next few months will be their opportunity to form partnerships that will last a lifetime.
04:13Most are families, pairs with their six-month-old cygnets hatched in Iceland.
04:18They will stay together until the next spring.
04:30They proclaim their arrival with a clear challenge to those already here.
04:34They, too, intend to claim a place on the lake.
04:49The male fights most of the necessary battles.
04:52But his mate always backs him up, and the pair celebrates a successful skirmish with an ecstatic triumph ceremony.
04:59There's a clear pattern to these encounters.
05:15Pairs consistently win against singletons.
05:19But the most dominant and successful of all are the families, mother, father and cygnets.
05:25This is a particularly powerful one.
05:27It has four young.
05:37Singletons, or even pairs, who come too close are quickly seen off.
05:45The cygnets enthusiastically join in the triumph ceremonies.
05:48As long as they stay close to their parents, they will be treated with respect by other birds.
05:54But if they stray, they will be shown no mercy.
06:12The parents will fight others on behalf of their young.
06:18And the cygnets will stay with their parents until the spring, when they'll be strong enough to fight their own battles.
06:30In the meantime, other members of the flock come to recognise and respect the most powerful families,
06:38and avoid confrontations where they can.
06:41An apparent peace breaks out on the lake.
06:43Other swans give the family a wide berth.
06:45The cygnets can now swim and feed without arguments.
06:47Other swans give the family a wide berth.
07:05The cygnets can now swim and feed without arguments.
07:12But not all seniorities are settled in such a straightforward way, particularly within groups.
07:23Chickens, when allowed to range freely in the farmyard, as these are, form themselves into small, tightly organised and remarkably stable groups.
07:47Usually, there's a cockerel, and then a number of hens around him, and maybe one or two other cockerels on the sidelines.
07:56One of the first studies ever made to find out how animals organise themselves in groups was done with a group of chickens like this.
08:06If there are ten or less in the group, then every bird knows every other individually.
08:12They move around in a flock, scratching around for whatever they can get, apparently harmoniously.
08:17But if I give them something they really like, then they reveal their true competitive nature.
08:24Watch this.
08:30This pale hen is particularly aggressive.
08:33If she doesn't get to the food first, she'll peck those who do so, until they give way to her.
08:49This dark hen, too, behaves in the same way and pecks everyone except the fierce pale hen whom she avoids.
09:03The result of these skirmishes is a peck order, a line of seniority in which each bird knows its place.
09:18And should the lowliest hen, at the bottom of the peck order, find a coveted morsel first,
09:24she'll be chased and harried by all the others until she gives it up.
09:28Clearly, all hens are not equal.
09:32Dominant ones hand out the punishment, junior ones get hen pecked.
09:36But for most of the time, the relationships between them seem very friendly,
09:41and the flock leads a quiet and productive life.
09:44It's the same with the cockerels.
09:46They, too, avoid confrontation.
09:48But every now and again, the senior cockerel has to remind the junior, who is boss,
09:53just in case they get it into their heads, that they want to steal his crown.
09:57Such peck orders occur in the wild as well.
10:14A group of caciques has established a colony high in a tree overlooking the Manu River in Peru.
10:20The males established who was senior to whom, early in the breeding season,
10:26with a series of disputes that none has forgotten.
10:29And those now determine who will get the pick of any food around.
10:33And, more importantly, who will consort with a female when she's ready to mate.
10:38The males compete for the right to display beside the clustered nests,
10:52which were built and are occupied by individual females alone.
10:59A subordinate male will always give way to a dominant one,
11:03just as chickens do in a farmyard.
11:05It's a waste of energy to go on fighting the same battles
11:08when the outcome will always be the same.
11:10The juniors snatch a mating if they can,
11:13but they may not succeed unless they move up in the rankings.
11:17So why do caciques put up with the tensions of social living,
11:21rather than going it alone?
11:23The reason becomes clear when the colony is threatened.
11:26A toucan, an avid eater of eggs and chicks.
11:30A single cacique is unlikely to deter a toucan,
11:37but all the members of the colony together,
11:39with their differences forgotten,
11:41can mount a highly effective defence.
11:43This nest is empty, but this one isn't.
11:59But this one isn't.
12:13A capuchin monkey, another most determined raider.
12:17So even subordinates in this community
12:29have a better chance of producing surviving chicks
12:32than if they were to nest in isolation
12:34with no effective defence against raiders.
12:39Lions too live in groups.
12:42The lionesses form the core of the pride.
12:45There may be a dozen or so,
12:46all of them closely related,
12:48mothers and daughters, sisters and aunts.
12:53And it's the lionesses that do most of the hunting.
12:56The two or three males, often brothers,
13:11fought as a team to drive off their predecessors
13:14and join the pride.
13:16And they will fight again if newcomers try to displace them.
13:19But for most of the time, they have a peaceful life.
13:22Living in groups for the lions brings several advantages.
13:29For one thing, they can tackle large, powerful prey,
13:33such as buffalo.
13:36These huge animals are three times the weight of a lion.
13:40A single hunter would be very unlikely
13:42to tackle a healthy adult buffalo.
13:44It simply wouldn't have the weight and sheer strength
13:47needed to bring one down.
13:49And it might well get injured in the attempt.
13:51But a pride, working together, has a chance.
13:59A preliminary chase serves to get the measure of the quarry
14:02and to isolate an individual.
14:04If one seems weaker than the rest,
14:06it will become the target.
14:21The lions attack.
14:22The lions attack.
14:34Despite the numbers pinning it down,
14:51the buffalo is still dangerous.
14:53It's finally killed, and the feasting begins.
15:10What about seniority and rank in this group?
15:25There's little squabbling or fighting.
15:27This kill has produced such a huge quantity of meat
15:30that there is more than enough for everyone.
15:33So those who haven't got a place at the carcass
15:35amiably await their turn.
15:37And that is just as well.
15:47Such lethally armed hunters as these brothers and these sisters
15:51could easily kill one another if a dispute became violent.
15:54Only in very hard times, when the pride is extremely hungry,
15:59will issues of priority be settled by fighting.
16:12Lions cooperating in prides dominate the harsh and ruthless world
16:16of the African plains.
16:18And the secret of that success is their cooperation.
16:21When they work together, no other hunters can match them.
16:24And this cooperation extends into other parts of their lives as well.
16:28The lionesses nurture their cubs as a team,
16:31taking turns to guard them
16:33and even, on occasion, suckling one another's infants.
16:39Baboons live in even bigger groups, up to 150 or so.
16:44This gives their young, who are defenceless for several years,
16:47the protection that comes from such numbers.
16:53This troop in Kenya is waking up,
16:56having spent the night in the relative safety
16:58of its regular sleeping cliff.
17:08Within a baboon troop,
17:09there's a fine balance between friendship and rivalry.
17:12As among lions, their societies consist largely of closely related mothers
17:17and their young.
17:18And it's the adult females who largely control affairs.
17:21The powerful males are all outsiders,
17:22who only gained acceptance to the troop
17:23by making friends with one or more females.
17:25Grooming is one way that they established such bonds.
17:40Taking charge of a female's baby is another.
17:42And a ferocious male can treat an infant with great tenderness,
17:44which is the more remarkable when you consider that he may not even be the father.
17:57In baboon society, a social favour like this will be remembered by the mother,
18:05and may well improve the male's long-term friendship with her,
18:09and the likelihood of him fathering her next baby.
18:12Males consolidate such relationships by encouraging females to join them for a careful grooming.
18:25Encounters with rival males, however, must be handled carefully.
18:29Lip-smacking here is a gesture of appeasement.
18:32Males pull other strange faces to act as clear come-on signals to passing females.
18:39Meetings can serve several functions.
18:58Seniorities and friendships are reaffirmed.
19:02Babies begin to learn the complex language of smells, gestures,
19:06and the importance of social relationships.
19:09By caring for an infant, a male demonstrates his commitment to its mother.
19:14And the babies, playing together, learn about making friends, as they must,
19:19if they are to achieve a good social position later in life.
19:23This babysitter misses the chance of making friends with a passing female,
19:37because he's surrounded by jealous males.
19:40If he had abandoned the baby, there might have been a squabble.
19:43As long as he holds on to it, he will be left alone by his rivals.
19:47But he has plenty of other opportunities.
19:50Being a good father figure makes a male a great favourite with the females.
19:54A young female passes the time of day, but she's not sexually receptive, and he's busy.
20:22In this complex society, social tensions can easily lead to conflict.
20:31And when a female is threatened and pursued by one male,
20:36she'll seek out another who is a regular ally and cling to him for support.
20:41With a friend to help her, she's now safe.
20:48And between them, some hard staring is enough to see off the aggressor.
20:53For baboons, it's not how big you are, but who you know that counts.
21:17Arguments and squabbles between adult animals striving to maintain their position within their community are common enough.
21:36But acts of assistance in which one adult animal goes to the aid of another that's got itself into difficulties, these are much rarer.
21:45But this sort of behaviour does seem to occur regularly in one species of animal,
21:51a colony of which is living in this hollow tree.
21:55It's not an animal that might immediately come to mind as an example of a caring, unselfish creature,
22:02but that apparently is what it is.
22:05On this pile of droppings, there are flecks of congealed blood, a characteristic sign of vampire bats.
22:22And the colony itself is roosting above me.
22:26These bats, or females, habitually roost as a group.
22:31If they move elsewhere, they will stick together and hang in the same sort of arrangement.
22:36Most are related, although by no means all.
22:39But every bat knows her regular companions well.
22:42At night, they fly off to look for blood.
22:49A donkey is a favourite target.
22:51One lands on its shoulder and shaves a slice of skin without the donkey even noticing.
22:59Another goes for its ear.
23:04The bat's saliva contains an ingredient that prevents blood from clotting,
23:08and it flows freely from the wound they make.
23:14A third bat tries a different point of attack.
23:17The bat on the ground still hasn't got a hold, but it's very hungry,
23:45and it makes one last attempt.
23:49But no, she won't feed tonight.
23:54On returning to the roost, she hangs up beside an old friend.
24:00She turns to her neighbour and licks her face repeatedly, begging for food.
24:05If she goes hungry for more than a day or two, she will die.
24:08But her friend regurgitates enough life-giving blood to keep her going until the following day.
24:15On another night, the situation may be reversed, and the bat that is receiving now will repay the gift if it's needed.
24:29But cheats, bats that refuse to give to a neighbour who once helped them, will quickly be detected, and in consequence may never be helped again.
24:38So for a vampire, it pays to help your neighbours whether they're related or not.
24:43Look after them, and they will look after you.
24:47Such mutual assistance is much more common among communities whose members are closely related.
24:53Dwarf mongooses live in groups of a dozen or so in the tunnels of old overgrown termite hills,
24:59and most of them are the children of one breeding pair.
25:16This is the old female. While she is alive, no other female here will breed.
25:21And this is her mate, the old male.
25:24They feed almost entirely on insects, which they scratch out of the ground and from rotten logs.
25:45And every day, the troop goes out to collect them.
25:48It's a very time-consuming business.
25:51A nice, big, crunchy beetle.
26:09A nice, big, crunchy beetle.
26:14But digging like this has its perils.
26:26With your head down in a hole, you can't see if an enemy approaches.
26:30And with your rump in the air, you're dangerously exposed.
26:33So while some hunt, other members of the colony are on guard duty.
26:40These sentinels, usually males, but sometimes females, will get their turn to feed in due course.
26:48The youngest babies are now coming out.
26:52Their mother can't always be with them.
27:06She has to spend much of her time feeding.
27:08And junior members of the colony take turns to babysit.
27:23One or two of these babysitters may replace the old breeders one day.
27:27But for now, the best they can do is to serve the colony.
27:31In doing so, they may promote their own genetic line.
27:34For the nurses are often the older sisters of the babies,
27:37who carry as many of their genes as their own young would.
27:40A marshal eagle, a most dangerous enemy.
27:57The sentinels keep a close eye on it to see if it's coming their way.
28:01If it does, they will whistle an alarm signal.
28:08.
28:10.
28:35The nurses groom their charges, they play with them, they catch insects for them.
28:42And though they have never been pregnant, they may even come in to milk and suckle them.
28:51By the middle of the day, it's very hot and many of the group feel in need of a snooze.
28:56And it's safe for them to drop off because some members of the family are still on guard.
29:05So, by taking turns to help out and waiting for a chance to breed,
29:12the mongooses are able to survive and continue their family line where, as pairs, they would surely fail.
29:23One mammal has taken this specialisation within the community to an extreme.
29:29Just how extreme hasn't been appreciated until quite recently.
29:33But that's hardly surprising, because the most that anyone normally sees of this amazing creature is no more than this.
29:40It's a powerful and industrious digger that spends its entire life underground.
30:04A naked mole rat.
30:06These creatures live in highly inbred groups of 80 or more,
30:11and feed on the gigantic underground tubers developed by some desert plants as a way of storing food and water.
30:17The trouble is that the mole rats have no way of knowing where these tubers are.
30:21All they can do is to dig away and hope they will eventually bump into one.
30:26So the colony is perpetually tunnelling.
30:28Digging in this hard ground requires teamwork.
30:38Some workers at the front end of the tunnel gnaw into the baked earth.
30:43A mole rat's lips close behind the long curved front teeth so that it doesn't get any of the earth into its mouth.
30:50Other members of the team behind kick the soil back along the tunnel until it reaches one of the surface exits.
31:06It's so unvaryingly hot here that the mole rats need no fur.
31:10Because they hardly ever come up into the light, eyes are of little use and they're virtually blind.
31:15So they run both backwards and forwards like tube trains.
31:26Not all the mole rats dig.
31:30A few, a little bigger than the tunnellers, spend most of their time lazing about in a large central chamber.
31:43These are soldiers.
31:45Some are male, some female, and they're saving their energies for an emergency.
31:50And here comes one.
32:01A snake has found its way down one of those exit holes.
32:06The workers flee in front of it, squeaking with alarm to rouse the soldiers.
32:15With those formidable teeth, the soldiers are quite capable of stabbing the snake to death.
32:28And they block the tunnel.
32:29Reinforcements arrive.
32:31Reinforcements arrive.
32:33Reinforcements arrive.
32:49The snake thinks better of it.
33:02The mother of the colony, the queen, is the only breeding female.
33:07She gives birth to a dozen or so young at a time and produces a new litter every 13 weeks.
33:13The father of the brood is one or other of the two oldest soldiers.
33:31But he's not as long-lived as the queen.
33:34A year or two of sexual activity seems to exhaust him, and he dies.
33:39His place will then be taken by another senior soldier.
33:42All these babies will become tunnellers.
33:51Some will later graduate to the ranks of the soldiers,
33:53but none of the females, as long as the queen lives, will become sexually mature.
33:58Why?
34:01The colony has a communal latrine, used by all, including the queen.
34:06The workers, when they visit it, deliberately anoint their naked skin with its contents.
34:13This gives them the colony's odour, so that they are recognised and accepted by all.
34:18But in doing that, they may commit themselves to a life of sterility.
34:22For the queen's urine contains a substance that helps to suppress the development of ovaries in others.
34:29The supply of the fertility suppressant will continue as long as the queen lives.
34:39Only when she dies will one of the female soldiers mature sexually and succeed to the throne.
34:48The queen spends most of her life lying in the chamber, surrounded by her soldiers.
34:53She doesn't dig.
34:55She doesn't fight.
34:55She concentrates her physical strength on producing, within her belly, huge broods of babies.
35:08So the ranks of the short-lived tunnellers are maintained to continue the digging that's essential to find food for themselves,
35:16their brothers and sisters, and their queen.
35:25These hard-working porters are also members of a society.
35:37But one which numbers not a few dozen, but several million.
35:42Nor are they just gathering straightforward food.
35:45They're taking part in a much more complex agricultural system.
35:48Leaf-cutting ants demolish plants morning, noon, and night.
36:02Heavy rain and direct sunshine are the only conditions that stop them.
36:09Every one of these workers is a female.
36:11And they're all sisters, working together in one of the most organised and tightly knit communities of all.
36:17They use their legs as calipers, guiding their jaws so that they cut a segment of a size that is the most economical to cut and most practical to carry.
36:41But they can't eat these leaf segments.
36:49Cellulose, the main constituent of leaves, apart from water, is very indigestible.
36:53They have to take all these pieces back to their underground nest for treatment.
36:59The journey may be down a tree trunk for 50 feet or more.
37:03And once on the ground, there may still be a hundred yards to go.
37:33Once inside the entrance of the nest, the leaves are carried down long corridors deep below ground.
37:53Here, in special chambers, they're taken over by a slightly smaller cast of worker who cut the leaves into smaller segments still.
38:07These chambers are gardens where the colony cultivates a special fungus.
38:11The leaf segments are the raw material on which the fungus will grow.
38:17But first, the segments must be processed.
38:20It could be very damaging if bacteria or spores of an alien fungus got into the nest and started to germinate like a weed.
38:27So the workers meticulously clean the surface of each piece by licking it.
38:39The edge of every segment is then chewed.
38:43This yields some food for the worker doing the job, for leaf sap is digestible.
38:48And it also prepares the leaf for the next stage.
38:53The garden chambers vary in size from an orange to a melon.
38:57But they're all filled with a honeycomb of grey, spongy material.
39:01And now, these smallest workers of all take over.
39:24They're a mere two millimetres long, the size of a grain of sand.
39:28Only these tiny dwarfs can enter the minute spaces within the gardens.
39:33They push the leaf fragments into the matrix and then plant tufts of fungus all over their pulped surface.
39:42Within 24 hours, the green of the leaf has almost completely disappeared beneath a tissue of white threads.
39:58A day or so later, and the threads of fungus begin to develop tiny knobs at their ends.
40:06This, at last, is the crop that the ants can eat.
40:12Some of the workers consume it there and then.
40:16Most is carried away to feed to developing grubs,
40:18and the other workers in the colony who laboured so hard gathering the leaf segments in the first place.
40:24One by one, the swollen ends of the threads are torn from the tangled mass.
40:45Sap, sunk from the edges of the leaves during their processing,
40:59is fed by a gardener to another worker who has duties elsewhere in the colony.
41:10Slowly, the swarms of workers complete the harvest.
41:15Now, the fungus is spent.
41:22Its remains and the mulch of leaves on which it grew has to be cleared out of the garden.
41:28The workers swarm all over the grey honeycomb, breaking it up.
41:32Every particle is carried up the corridors and taken out of the nest.
41:50Long processions of workers set off for the exits.
42:08Here, out in the open, by the side of the nest, they have their refuse tip.
42:12To be continued...
42:18So one cycle of fungus cultivation is completed.
42:47And the scale of their operations is enormous.
42:51They can strip an entire tree of its leaves in a single night.
42:55Their pathways extend for a hundred yards in all direction.
42:59The nest is 20 feet across and it goes down for as much as 18 feet.
43:05Inside there are a thousand or so chambers where the ants have their gardens and where they live.
43:11And it's virtually impregnable.
43:14Even the vibrations of my footsteps are enough to bring out the defenders.
43:24These soldiers are 300 times heavier than the little dwarfs working in the gardens.
43:30They bite any alien thing, shoes, socks, anything.
43:35As long as they only bite my clothing, they're no problem.
43:38If they got onto my flesh, they would have me hopping about, for they can slice a very painful slit in your skin.
43:44And they seldom let go.
43:46Once they've fastened their jaws, they stay fastened, even if the rest of their body gets torn off.
43:52Soldiers are expendable.
43:54Their task is to protect the one single individual in the colony who is indispensable.
44:00The queen, mother of all the members of the colony.
44:04She is as big as a newborn mouse.
44:07On her nuptial flight, she was impregnated by three or four males.
44:12And the sperm they gave her then lasts her for the rest of her long and productive life.
44:17The workers continually groom and clean every part of her great body.
44:40Some attend her rear, waiting to collect the eggs she produces in bursts.
44:45She may lay a million a year.
44:48Some are fertilized from her sperm store.
44:51Others are not, but they too will hatch.
44:55One appears, a tiny white bead.
44:58A worker waits for it to emerge completely, feeling it delicately with its jaws.
45:04It picks it off and takes it away to the nursery chambers.
45:10The grubs that develop from fertilized eggs,
45:13mostly become members of the exclusively female workforce.
45:17The way they are fed by the workers determines which of the six different castes they will be.
45:23Unfertilized eggs develop into males,
45:26who fly out of the nest to mate with young winged queens and establish new colonies.
45:32Once these ants start on adult life,
45:34they will not be able to change roles as mole rats or dwarf mongooses can.
45:39Their destiny is fixed.
45:41The first ants, back in the evolutionary past, almost certainly operated as single individuals,
45:54as many species of bear wasp and bee relatives still do today.
45:59Over millions of years they came to live in communities of increasing size and complexity.
46:04And now that process has come full circle.
46:07By producing individuals specialized to do particular jobs in their society,
46:12five million insects have become effectively one.
46:16But what a superbly efficient one.
46:19It's not the monkeys or the rodents or indeed the human beings who dominate the forest.
46:26It's the tiny ant that by multiplying itself has turned itself into a super organism.
46:32A complex, highly disciplined society.
47:02йoow.
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