0:01:04 > 0:01:08DULL CROAKS
0:01:38 > 0:01:43These great skuas bonxies here in Shetland
0:01:43 > 0:01:48are among the most aggressive and ferocious of birds.
0:01:50 > 0:01:57They're attacking me now because I'm approaching one of their nests where there are chicks.
0:01:57 > 0:02:02They rob other birds of their food, actually in the air.
0:02:02 > 0:02:07And they are extremely skilful hunters. They're killers!
0:02:14 > 0:02:18Their hungry chicks, waiting in the nest for food,
0:02:18 > 0:02:22make them especially determined.
0:02:22 > 0:02:26They seek their prey in the huge colony of sea-birds nesting on the cliffs nearby.
0:02:30 > 0:02:34KITTIWAKES CALLING
0:02:34 > 0:02:39Few creatures in the world are not forever caught up in duels,
0:02:39 > 0:02:42like those being fought out here,
0:02:42 > 0:02:47duels that have shaped their bodies and govern their daily behaviour.
0:02:47 > 0:02:52The skua's tactic is to cruise so close to the cliff
0:02:52 > 0:02:59that the kittiwake parents are frightened off their nests, leaving the chicks unprotected.
0:02:59 > 0:03:06The kittiwake chicks are almost full-grown, and the skuas want them to feed to THEIR young.
0:03:53 > 0:03:59That bird actually caught an adult kittiwake in mid-air.
0:04:16 > 0:04:19The skuas go first for the liver.
0:04:19 > 0:04:24With crops stuffed full, they will be able to feed their chicks today.
0:04:31 > 0:04:37Many different kinds of birds, having spent most of the year out at sea,
0:04:37 > 0:04:40come to these cliffs in the spring to nest.
0:04:40 > 0:04:42Each has its own favoured territory.
0:04:42 > 0:04:46In parts where there is turf and soil, puffins dig their nest holes.
0:04:46 > 0:04:51Sitting beside them, they are relatively safe.
0:04:51 > 0:04:53If danger looms, they can duck inside their holes.
0:04:55 > 0:04:59It's when they're in the air that they are really vulnerable.
0:05:03 > 0:05:07Here, the greater black-backed gull is on patrol.
0:05:07 > 0:05:11It's substantially bigger than the lesser black-back.
0:05:15 > 0:05:17It has a wing-span of over five feet
0:05:17 > 0:05:22and the manoeuvrability of a fighter aircraft.
0:05:22 > 0:05:27The puffins, with wings and feet that also serve in swimming
0:05:27 > 0:05:29and diving, are less agile in the air.
0:05:53 > 0:05:56Flying in flocks reduces an individual's risk,
0:05:56 > 0:05:58but that's not always possible.
0:07:19 > 0:07:24With the puffin almost swallowed, the gull has at last got a meal.
0:07:31 > 0:07:34Or has it?
0:07:45 > 0:07:48The murdering robber has been robbed.
0:07:55 > 0:07:59There are other animals that spend most of their life at sea,
0:07:59 > 0:08:02but come to land for a few weeks each year
0:08:02 > 0:08:04seals and sea-lions.
0:08:11 > 0:08:15These are South American sea-lions off the coast of Patagonia.
0:08:15 > 0:08:19They can't give birth while they're swimming, as whales and dolphins do.
0:08:19 > 0:08:21They have to come ashore.
0:08:21 > 0:08:29In dense groups, they are a great temptation to any hunter that can reach them.
0:08:34 > 0:08:37Their nursery beach seems secure.
0:08:37 > 0:08:43On the landward side are cliffs, on the other side is the sea.
0:08:43 > 0:08:47But the sea itself can harbour enemies.
0:08:56 > 0:09:00A killer whale, 30-feet long, eight tons in weight.
0:09:00 > 0:09:05Every year, the same group of about a dozen of them assemble off the sea-lion nursery to hunt.
0:09:05 > 0:09:12For sea-lions to venture into deep water here is dangerous.
0:09:12 > 0:09:15It's much safer to stay in the shallows if they can.
0:09:44 > 0:09:50In one or two places, channels allow the whales to get really close to the beach.
0:09:50 > 0:09:52Those are the danger spots.
0:10:20 > 0:10:24To get off the beach, the killer has to thrash its body.
0:10:29 > 0:10:33No other whale deliberately beaches itself like this,
0:10:33 > 0:10:37or has perfected this method of getting back to sea.
0:10:54 > 0:10:56As long as the sea-lions stay well up the beach,
0:10:56 > 0:10:58you might think they'd be safe.
0:10:58 > 0:11:01But the hungry whales are very daring.
0:11:15 > 0:11:18Now several of the whales are hunting in a group.
0:11:39 > 0:11:43That sea-lion was keeping just ahead of one of the whales,
0:11:43 > 0:11:45but was caught by another it probably hadn't seen.
0:12:52 > 0:12:57This savage beating may be to separate hide from flesh.
0:13:02 > 0:13:08But very often, the successful hunter takes its victim out to sea without even killing it.
0:13:13 > 0:13:19And there it plays with its catch as if it were exulting in triumph.
0:14:00 > 0:14:08To get all the food it needs, a killer whale must catch at least three sea-lion pups a day,
0:14:08 > 0:14:14and every day throughout the breeding season, this group of skilled hunters do just that.
0:14:43 > 0:14:46The Indian fishing cat hunts at night.
0:14:46 > 0:14:51A bit larger than a domestic cat, it feeds on all kinds of prey,
0:14:51 > 0:14:56from mice and rabbits to frogs and birds.
0:14:56 > 0:14:59But its speciality is fish.
0:15:06 > 0:15:10This pair have found an ideal opportunity
0:15:10 > 0:15:15a drying river where the fish have been concentrated by the shrinking water into a pool.
0:15:17 > 0:15:19Even so, it's not easy.
0:15:19 > 0:15:25It requires stealth, lightning reflexes, endless patience,
0:15:25 > 0:15:28and perfect co-ordination between eye and paw.
0:15:28 > 0:15:32These cats have brought such skills to perfection.
0:16:42 > 0:16:47Slugs, you might think, are hardly a challenge to a hunter.
0:16:47 > 0:16:53Very few things want to hunt them. This is one the thirst snake.
0:16:53 > 0:16:57Its hunting technique is simplicity itself.
0:16:57 > 0:17:01The slug's slime which makes it so unappetising
0:17:01 > 0:17:05provides the trail which the snake follows.
0:17:39 > 0:17:43But swallowing such a slimy mouthful isn't easy.
0:17:43 > 0:17:46The snake dislocates its lower jaw
0:17:46 > 0:17:51and twists it forward so that it snags the slug with its teeth.
0:17:58 > 0:18:03Then a yawn puts the lower jaw back into position.
0:18:03 > 0:18:06Not all the hunted give in easily.
0:18:06 > 0:18:11Many have ways of deterring hunters that try to make a meal of them.
0:18:21 > 0:18:27An American opossum may think this frog will make an easy mouthful. It's quite wrong.
0:18:27 > 0:18:31First, the frog inflates its lungs
0:18:31 > 0:18:35so that it looks as big and as formidable as possible.
0:18:35 > 0:18:39- Then it lets off an amazing alarm. - CROAKING SCREAM
0:18:59 > 0:19:04The whole performance is more than enough to put off the possum.
0:19:04 > 0:19:08In Australia, dingoes too can be put off by bluff.
0:19:08 > 0:19:11A frilled lizard.
0:19:26 > 0:19:29The frill is nothing but skin,
0:19:29 > 0:19:33but it disconcerts the dingo long enough
0:19:33 > 0:19:34to allow the lizard to escape.
0:19:44 > 0:19:47This, however, is no bluff.
0:19:47 > 0:19:52Hunters like this viper carry poison to kill their prey.
0:19:52 > 0:19:57And the hunted use it too, as a deterrent.
0:19:57 > 0:20:00This tomato frog, when threatened,
0:20:00 > 0:20:06exudes a milky poison that would make any aggressor very ill indeed.
0:20:12 > 0:20:17The problem about poison as a defence is that,
0:20:17 > 0:20:23by the time you've convinced your attacker you're not worth eating, it has mauled or killed you.
0:20:23 > 0:20:31So many animals that have poison advertise the fact in advance. Look at this little creature.
0:20:35 > 0:20:38It's a spotted skunk.
0:20:38 > 0:20:42Like the bigger striped skunk that also lives here in the southern United States,
0:20:42 > 0:20:49it has glands that squirt a liquid that smells so appalling it can make you sick.
0:20:53 > 0:20:55I'm going to press my luck a bit!
0:20:57 > 0:21:03It doesn't want to squirt needlessly, so it gives a warning.
0:21:06 > 0:21:12It's an eloquent display of gymnastics to back up its warning spots.
0:21:14 > 0:21:20How better could you call attention to the spray-gun under your tail?
0:21:20 > 0:21:26I'm not going to get any closer because I don't want to be sprayed!
0:21:31 > 0:21:37Salamanders also put on gymnastic displays to declare that they have chemical weapons.
0:21:37 > 0:21:41In their case, it's in their skin.
0:21:41 > 0:21:49Having jerked convulsively into an extraordinary contortion, they stay there, transfixed.
0:21:52 > 0:21:55This one's warning colours are on its belly only,
0:21:55 > 0:21:58so when danger threatens, it throws itself on its back.
0:22:04 > 0:22:11And this one has its poison in a line of sacs along its flanks which it can release
0:22:11 > 0:22:15by the drastic method of sticking its ribs through its skin, tearing them open.
0:22:18 > 0:22:24Some poisonous bugs carry their "keep-off" signs like banners on their legs.
0:22:24 > 0:22:30And these add an additional trick. They keep together in a swarm.
0:22:33 > 0:22:41If a bird misguidedly takes one, it won't peck at the others with that nasty taste in its mouth.
0:22:45 > 0:22:50Black and yellow is a colour code that is widely understood.
0:22:50 > 0:22:55It's used not only by wasps but by salamanders and snakes, and caterpillars like this one.
0:22:55 > 0:23:01These long hairs are also poisonous.
0:23:03 > 0:23:09The caterpillar walks around with the confidence of the well-armed.
0:23:09 > 0:23:12Some only PRETEND to be well-armed.
0:23:12 > 0:23:16This may look like an ant with a sting,
0:23:16 > 0:23:22but the ant body is a mask on a harmless, edible, plant-hopper.
0:23:22 > 0:23:28This little creature looks like a spider, and so does this.
0:23:28 > 0:23:30In fact, both are fruit-flies.
0:23:30 > 0:23:36They have neither poison-fangs nor stings, and could be eaten.
0:23:38 > 0:23:40Here is a real spider.
0:23:40 > 0:23:44It signals with its palps and legs, as it would to another spider.
0:23:53 > 0:23:59And the fly responds by waving its black and white wings in a similar way
0:23:59 > 0:24:03It's mimicking the spider's "keep away" sign.
0:24:03 > 0:24:05And it works!
0:24:07 > 0:24:11You can also protect yourself by concealment.
0:24:11 > 0:24:16Insects are the great masters at doing this.
0:24:16 > 0:24:20A stick? No, an insect.
0:24:20 > 0:24:26This is its head, with its front legs stretched up beside it.
0:24:26 > 0:24:32You can recognise it for what it is only when it walks.
0:24:46 > 0:24:48A band of moss, perhaps?
0:24:48 > 0:24:55No, another insect, but lying so flat against the twig that it seems almost a part of it.
0:25:04 > 0:25:07Only its antenna lifted above the twig,
0:25:07 > 0:25:10and a slight adjustment of position, give the game away.
0:25:14 > 0:25:18Dead leaves lie all over a forest floor,
0:25:18 > 0:25:23so an insect mimicking them can wander undetected over a wide area.
0:25:28 > 0:25:29It's a kind of bush cricket.
0:25:31 > 0:25:35And this insect mimics living leaves.
0:25:35 > 0:25:41Its vivid green leaf-covers are veined like real leaves.
0:25:43 > 0:25:46Green flanges sprout from its legs.
0:25:46 > 0:25:52Few of those that are hunted among leaves can have a better concealment than this.
0:25:58 > 0:26:01Thorn bugs.
0:26:01 > 0:26:06Like many bugs, they produce excretions that are collected by ants.
0:26:06 > 0:26:10Ants seem to know which are thorns and which are bugs.
0:26:19 > 0:26:22But two can play at that game.
0:26:22 > 0:26:30What could look more innocent than this orchid blooming in the Malaysian rainforest?
0:26:30 > 0:26:35Its flowers are bright, proclaiming the sweetness of their nectar and attracting insects.
0:26:36 > 0:26:40But even in such a lovely thing, danger can lurk.
0:26:40 > 0:26:48Sitting on it, exactly matching the colour of the orchid petals, is a mantis. It's facing left.
0:26:51 > 0:26:55It's waiting, motionless, for the butterfly.
0:27:31 > 0:27:34Beside the entrance of a termite hill,
0:27:34 > 0:27:39a pile of refuse tipped out from the nest by termite workers.
0:27:39 > 0:27:43On it, another hunter, lurking in disguise.
0:27:43 > 0:27:45It's an assassin bug.
0:27:49 > 0:27:53It throws particles of refuse on to its body
0:27:53 > 0:27:57not to hide from its prey, termites, which are blind
0:27:57 > 0:28:02but to hide from birds and other creatures that might eat IT.
0:28:11 > 0:28:13Its cloak of droppings, however,
0:28:13 > 0:28:19may conceal it from the termites by giving it a protective smell.
0:28:19 > 0:28:25The industrious workers are unaware that there's an enemy there, until it's too late.
0:28:44 > 0:28:49Mimicry doesn't always deflect attention. Sometimes it attracts it.
0:28:49 > 0:28:54A death-adder from Northern Australia.
0:28:55 > 0:29:01And this could be its next meal a skink, searching for worms.
0:29:05 > 0:29:09Perhaps this is what it's seeking.
0:29:21 > 0:29:24In fact, it's the tip of the death-adder's tail.
0:29:45 > 0:29:48That was a near miss!
0:29:48 > 0:29:53Lures can also be used in defence.
0:29:53 > 0:29:57A blue tit, hunting for food, may overlook a camouflaged hawk moth.
0:29:59 > 0:30:04But if it investigates, the moth suddenly exposes its hind wings.
0:30:07 > 0:30:11The eye-spots don't alarm THIS tit, but they induce an attack.
0:30:11 > 0:30:18Instead of getting a lethal peck on its head, the moth is struck harmlessly on its wing.
0:30:18 > 0:30:24Eye-spots give this caterpillar an almost snake-like appearance.
0:30:24 > 0:30:28And these tentacles, which release a nasty smell, heighten that resemblance.
0:30:34 > 0:30:38Could this really be an imitation of a snake's forked tongue?
0:30:38 > 0:30:46Could the caterpillar be mistaken for a snake when it is only inches long? We can only guess.
0:30:46 > 0:30:51And this is an even greater mystery.
0:30:51 > 0:30:54It's a frog and, like most frogs,
0:30:54 > 0:30:57is hunted by snakes.
0:31:15 > 0:31:20The centres of these eye-spots carry poison glands,
0:31:20 > 0:31:25but the snake couldn't see them from the front.
0:31:25 > 0:31:30So just how does having a face on its bottom protect the frog?
0:31:30 > 0:31:33No-one knows.
0:31:33 > 0:31:37Big eyes undoubtedly attract attacks.
0:31:37 > 0:31:44As this frog has real ones, it needs to conceal them rather than display them.
0:31:44 > 0:31:46It lives in bromeliad plants,
0:31:46 > 0:31:51a favourite hunting-ground for small snakes.
0:31:53 > 0:32:01By reversing into the heart of the plant, it conceals everything except the top of its head
0:32:01 > 0:32:07which is protected by a special helmet, a bony shield.
0:32:27 > 0:32:34So, many animals have developed techniques for preventing other animals from eating them.
0:32:34 > 0:32:41High-speed sprints, jinking runs, distraction displays, near-perfect camouflage,
0:32:41 > 0:32:46even taking on disguises that make them look like hunters themselves.
0:32:46 > 0:32:52But there is one animal against which none of these is a defence,
0:32:52 > 0:32:56one hunter which is invariably successful this one.
0:32:58 > 0:33:03Beneath this log is an immense ball of ants.
0:33:03 > 0:33:10Its outer surface is a lacy veil formed by individuals clinging to one another's legs.
0:33:10 > 0:33:17Altogether, there are about three quarters of a million. They are army ants. This is their bivouac.
0:33:20 > 0:33:26A raiding force of workers escorted by a guard leaves the bivouac.
0:33:26 > 0:33:31They are almost blind, but they are following a scent trail
0:33:31 > 0:33:34laid down by scouts who are foraging ahead.
0:33:42 > 0:33:48Few things are safe from them, not even a giant spider.
0:34:13 > 0:34:19The sting of a scorpion is useless against such tiny aggressors. They're too small to hit,
0:34:19 > 0:34:22and too numerous.
0:34:33 > 0:34:37A wasps' nest is a major prize.
0:34:37 > 0:34:42The adult wasps, even though they have powerful stings, can't repel the ants,
0:34:42 > 0:34:45and they watch helplessly as their colony is pillaged.
0:34:57 > 0:35:01The fat grubs are hauled from their cells, butchered, and carried off.
0:35:07 > 0:35:12The bigger victims are cut up for easier transport,
0:35:12 > 0:35:15and carried back to the queen and the workers.
0:35:32 > 0:35:37A caterpillar's camouflage did not save it.
0:35:45 > 0:35:50A ring-shaped segment from a millipede is caught on a spike.
0:35:54 > 0:36:00In some places, the soldiers form living bridges across which the porters run.
0:36:03 > 0:36:10The bite of the ants' jaws and the sting in their tail is so painful you daren't get close.
0:36:10 > 0:36:14So studying them is very difficult.
0:36:14 > 0:36:19We know very little of what goes on in the heart of such a bivouac.
0:36:19 > 0:36:23But this optical probe may help us find out.
0:36:31 > 0:36:37The bivouac has an internal structure, with walls made by the ants clinging together.
0:36:37 > 0:36:42You have to be careful. Even though the probe has been greased, some soldiers manage to run up it.
0:36:46 > 0:36:50Here is the nursery, full of young developing grubs.
0:37:02 > 0:37:09After two weeks or so in camp, the eggs that the queen has laid in such numbers are hatching.
0:37:09 > 0:37:13The grubs need feeding, and the entire army once more starts to march.
0:37:23 > 0:37:26The workers carry the baby grubs.
0:37:43 > 0:37:49Soldiers, huge jaws agape, guard the sides of the route.
0:37:49 > 0:37:53The army makes temporary camp each night
0:37:53 > 0:37:58until, after about two weeks, it bivouacs and repeats the cycle.
0:38:02 > 0:38:07The most powerful hunters in the bird world are hawks and eagles.
0:38:07 > 0:38:14But the Harris hawk, in the deserts of New Mexico, has a particular skill it hunts in groups.
0:38:24 > 0:38:29The team of half a dozen or so assembles in the morning
0:38:29 > 0:38:32and begins to search the countryside.
0:38:35 > 0:38:39Their look-out posts are the great pillars of the saguaro cactus.
0:39:07 > 0:39:11The cacti are splendidly tall,
0:39:11 > 0:39:15but they don't appear to be very comfortable.
0:39:20 > 0:39:25And the prickly pear is hardly any better.
0:39:40 > 0:39:43A pack rat!
0:39:54 > 0:39:59In this thorny tangle, it's hard to get a clear sight to pounce.
0:39:59 > 0:40:03Some of the hawks go down to try and chase the rat out.
0:40:06 > 0:40:10Since the rat is so much quicker on the ground than they are,
0:40:10 > 0:40:13they'll only catch it if there are several of them.
0:40:38 > 0:40:45They've lost the rat, but found bigger prey, a cottontail rabbit.
0:40:45 > 0:40:50The two on the ground chase it out.
0:40:50 > 0:40:52Those perching now get a clear sight.
0:41:03 > 0:41:08Once the kill is made, the entire team gathers,
0:41:08 > 0:41:11and each bird tears off a share.
0:41:11 > 0:41:17One bird by itself is unlikely to have made such a kill in such country as this.
0:41:17 > 0:41:24But were the birds working in a team with a plan? Probably not.
0:41:24 > 0:41:30Individual birds do not regularly play the same role.
0:41:30 > 0:41:35Each reacted to the movements of the rabbit, and benefited from its companions doing the same.
0:41:37 > 0:41:44In the forests of the Ivory Coast in West Africa live animals that are our closest relatives.
0:41:46 > 0:41:50Chimpanzees. A peaceful scene of jungle harmony.
0:42:06 > 0:42:09You don't normally think of THEM as hunters,
0:42:09 > 0:42:15more as gentle vegetarians, munching fruit and picking leaves.
0:42:15 > 0:42:22But if you follow them in their true home, these forests in West Africa,
0:42:22 > 0:42:25you discover that they ARE hunters.
0:42:25 > 0:42:31What's more, they hunt in teams and have a more complex strategy
0:42:31 > 0:42:35than any other hunting animal except...
0:42:35 > 0:42:40- CHIMPANZEE SHRIEKS - ..except, of course...man.
0:42:42 > 0:42:49One of the hunters, the experienced male, is sitting right there.
0:42:59 > 0:43:03This is the time they hunt the wet season.
0:43:03 > 0:43:08Their regular prey is monkeys, but they're selective.
0:43:08 > 0:43:13A Diana monkey, a big species, and one they seldom tackle.
0:43:32 > 0:43:35A spot-nosed monkey.
0:43:39 > 0:43:44Red colobus. They're much better jumpers than chimps,
0:43:44 > 0:43:46and being half their weight,
0:43:46 > 0:43:51they go on much thinner branches, so in theory a chimp can't catch them.
0:43:51 > 0:43:58They must work as a team, and half a dozen males in this group of 60 regularly do so.
0:44:07 > 0:44:13This is one of them. From his walk, it's clear that the search for prey has started.
0:44:13 > 0:44:17The other members of the team are not far away.
0:44:22 > 0:44:25They've been following the monkeys for about 20 minutes, looking for an opportunity.
0:44:32 > 0:44:40The technique they'll almost certainly use is that one of them will drive the colobus ahead of him
0:44:40 > 0:44:43and there will be others on either side
0:44:43 > 0:44:48the blockers who make no attempt to catch the monkey.
0:44:48 > 0:44:52Then there are chasers who grab the monkey if they can,
0:44:52 > 0:44:56and finally a male who goes ahead to ambush it,
0:44:56 > 0:44:59so bringing the whole trap closed.
0:45:02 > 0:45:05The monkeys are now getting alarmed.
0:45:08 > 0:45:12A driver's going up to prevent the group from settling
0:45:12 > 0:45:16and to drive them towards an area where they are more easily trapped.
0:45:35 > 0:45:39That's one of the blockers that has quietly come ahead of the colobus
0:45:39 > 0:45:42and is half-way up the tree.
0:45:42 > 0:45:46He's deliberately making himself conspicuous.
0:45:50 > 0:45:52They're all in position.
0:45:52 > 0:45:59The drivers and blockers have gone up, and the one who will close the ring has gone up too.
0:45:59 > 0:46:02The colobus will be very lucky if they escape now.
0:46:08 > 0:46:12CHIMPS SHRIEKING
0:46:15 > 0:46:17They've got one!
0:46:19 > 0:46:21PIERCING SCREAMS
0:46:27 > 0:46:30The hunters are tearing it apart.
0:46:30 > 0:46:34Everyone hunters in the trees, spectators on the ground
0:46:34 > 0:46:36is screaming with excitement.
0:46:55 > 0:47:01And now the kill is brought down so that the females and others can share it.
0:47:18 > 0:47:25And there's the reward for that long chase the divided body of a colobus monkey.
0:47:25 > 0:47:29These blood-stained faces...
0:47:29 > 0:47:32may well horrify us.
0:47:32 > 0:47:39But we might also see in them the faces of our long-distant hunting ancestors.
0:47:39 > 0:47:45And if we are appalled by that mob violence and blood-lust,
0:47:45 > 0:47:51we might also see in it the origins of the team-work
0:47:51 > 0:47:58that has, in the end, brought human beings many of their greatest triumphs.