0:00:13 > 0:00:17In Galapagos, this majestic tortoise is in a bit of discomfort.
0:00:19 > 0:00:22He's got an itch he can't scratch.
0:00:24 > 0:00:25The answer?
0:00:25 > 0:00:28To partner up with a finch.
0:00:29 > 0:00:33The finch pecks out all those irritating ticks and grubs.
0:00:36 > 0:00:38The bird gets a meal,
0:00:38 > 0:00:41the tortoise gets relief.
0:00:44 > 0:00:45Everyone's a winner!
0:00:51 > 0:00:53There are times in life
0:00:53 > 0:00:55when all you need is a little help.
0:00:59 > 0:01:03It could come from members of your own family,
0:01:03 > 0:01:05or from some more unusual allies.
0:01:09 > 0:01:11Across the natural world,
0:01:11 > 0:01:14some extraordinary partnerships between animals
0:01:14 > 0:01:16are being discovered.
0:01:19 > 0:01:21Whether it's a lion and a lizard...
0:01:22 > 0:01:26..or a raven and a wolverine...
0:01:28 > 0:01:30..no matter where they are on the food chain,
0:01:30 > 0:01:34many creatures have learned that life can be a bit easier
0:01:34 > 0:01:36when you find a perfect partner.
0:01:45 > 0:01:48Out in the wild, survival is paramount,
0:01:48 > 0:01:51but even in this pristine wilderness,
0:01:51 > 0:01:54just staying clean is a daily challenge.
0:01:55 > 0:01:57One way is to enlist some help,
0:01:57 > 0:02:01but that can depend on whether there's mutual benefit.
0:02:19 > 0:02:23Across Africa, hippos are considered among the most dangerous of animals.
0:02:29 > 0:02:31They can be unpredictable
0:02:31 > 0:02:32and highly aggressive.
0:02:38 > 0:02:41They certainly appear tough enough to look after themselves.
0:02:45 > 0:02:50But their impressive hides are prone to irksome parasites.
0:02:54 > 0:02:57Unable to pick up a stick and scratch their own back,
0:02:57 > 0:02:59they've gone into partnership.
0:03:03 > 0:03:06Meet the barbel,
0:03:06 > 0:03:08a hippo's best friend.
0:03:14 > 0:03:19These graceful goliaths are trailed by shoals of these loyal fish.
0:03:20 > 0:03:23They even eat the droppings - what a bonus!
0:03:37 > 0:03:41Once in a comfortable spot the barbels get to work,
0:03:41 > 0:03:44nibbling away at all the hippo's unwanted guests.
0:03:46 > 0:03:48It's a bit like a spa treatment,
0:03:48 > 0:03:52complete with facial, full body exfoliation
0:03:52 > 0:03:55and it seems to lull the hippos into a kind of trance.
0:04:04 > 0:04:08Thanks to the food stuck to the hippos' teeth, the industrious fish
0:04:08 > 0:04:11are able to feed on exotic vegetation from the land,
0:04:11 > 0:04:13which would otherwise be out of their reach.
0:04:15 > 0:04:17Timing and agility are essential here.
0:04:22 > 0:04:25It's a peculiar pairing, but it seems to work.
0:04:27 > 0:04:30The fish get a feast and the hippos submit quite happily,
0:04:30 > 0:04:35perhaps making us see these aquatic curmudgeons in a different light.
0:04:45 > 0:04:48Many creatures need help with their personal hygiene.
0:04:51 > 0:04:53Even in the depths of the sea
0:04:53 > 0:04:55are fish which could do with a bit of a once over,
0:04:55 > 0:04:59but, at times, finding the right cleaner
0:04:59 > 0:05:01can require a little more effort.
0:05:04 > 0:05:05For these jacks,
0:05:05 > 0:05:08their skin parasites are more than just annoying.
0:05:10 > 0:05:13If not removed, they can reduce their growth.
0:05:15 > 0:05:20This specialist cleaner fish, the wrasse, offers relief.
0:05:24 > 0:05:28But the brightly coloured wrasse is recognised by many other fish,
0:05:28 > 0:05:31all wanting the same service.
0:05:32 > 0:05:34It leaves the jacks with a problem
0:05:34 > 0:05:37as there just aren't enough cleaner wrasse go around.
0:05:37 > 0:05:41So the jacks have to find a more precarious solution.
0:05:47 > 0:05:51At first glance, it seems an almost suicidal option.
0:05:59 > 0:06:03This is a silver tip shark and could easily eat a jack.
0:06:11 > 0:06:14But these sharks have skin like sandpaper
0:06:14 > 0:06:18and bumping into their flanks helps scrape off unwanted parasites.
0:06:29 > 0:06:34Soon swarms of jacks pursue the sharks, all itching to have a go.
0:06:41 > 0:06:45A dangerous game, but perhaps one that's tolerated.
0:06:49 > 0:06:55Could all this bumping around also help to exfoliate shark's skin?
0:06:55 > 0:06:59A case of you scratch my back and I'll scratch yours.
0:07:02 > 0:07:06Eventually, though, the sharks have had enough
0:07:06 > 0:07:09of being used as mobile loofahs and they're off.
0:07:09 > 0:07:12For the jacks, they must be doubly relieved -
0:07:12 > 0:07:14to be rid of their itches and to be alive.
0:07:19 > 0:07:24On the African savanna, another animal is about to take a big risk.
0:07:26 > 0:07:30He's very hungry and he knows where there is guaranteed food,
0:07:30 > 0:07:33but catching it will mean getting up close and personal
0:07:33 > 0:07:36to one of the fiercest predators around.
0:07:43 > 0:07:46After a hearty meal of wildebeest,
0:07:46 > 0:07:50the lions are doing their best to take a siesta.
0:07:50 > 0:07:52But under the scorching hot sun,
0:07:52 > 0:07:56they are surrounded by irritating and relentless flies.
0:08:03 > 0:08:06Step up Mr Lizard,
0:08:06 > 0:08:09perhaps the bravest cleaner in the world.
0:08:18 > 0:08:22Lions do eat lizards, but having already had a much larger meal,
0:08:22 > 0:08:24they are unlikely to need dessert.
0:08:30 > 0:08:34Still, best to be cautious as lions can be notoriously short-tempered,
0:08:34 > 0:08:36even if you're doing them a favour.
0:08:56 > 0:08:59It takes a bit of courage and skill,
0:08:59 > 0:09:01which not all the lizards possess.
0:09:09 > 0:09:11Across the world, their lizard cousins
0:09:11 > 0:09:14have struck up a similarly special relationship
0:09:14 > 0:09:16with another type of lion.
0:09:17 > 0:09:20The lava lizards of the Galapagos
0:09:20 > 0:09:22rid their seal lion friends of flies,
0:09:22 > 0:09:25which can be ticklish nuisance.
0:09:25 > 0:09:29Here, the busy cleaners appear a lot less cautious and much more welcome.
0:09:37 > 0:09:38Back on the savanna,
0:09:38 > 0:09:42it seems that as long as the lizards let the sleeping lions lie,
0:09:42 > 0:09:44they will be rewarded with a tasty snack.
0:09:46 > 0:09:50How appreciative the lions actually are of their fly-swatting efforts,
0:09:50 > 0:09:51well, who knows?
0:09:55 > 0:09:59Some animal partnerships go much further than just cleaning.
0:10:05 > 0:10:07When you need a bit of home help
0:10:07 > 0:10:11or you're having a spot of bother with your neighbours,
0:10:11 > 0:10:14it can be worth considering a lodger.
0:10:27 > 0:10:32In the coral reefs is perhaps one of nature's oddest couples.
0:10:33 > 0:10:38This lugubrious goby has been offered lodging from a shrimp.
0:10:43 > 0:10:47The shrimp is the perfect homemaker,
0:10:47 > 0:10:52always cleaning, digging extensions and carrying out home improvements.
0:10:54 > 0:10:57Yet its chosen lodger seems rather lazy,
0:10:57 > 0:11:01just hanging about and occasionally getting in the way.
0:11:19 > 0:11:21Despite first impressions,
0:11:21 > 0:11:25the goby is, in fact, crucial to this partnership
0:11:25 > 0:11:28as the shrimp is almost entirely blind.
0:11:33 > 0:11:36The goby, on the other hand, has excellent eyesight
0:11:36 > 0:11:39and remains constantly alert.
0:11:42 > 0:11:44So, when the shrimp is outside,
0:11:44 > 0:11:48it continuously flicks one of its antennae over the goby
0:11:48 > 0:11:51to make sure it's still there and the coast is clear.
0:12:05 > 0:12:09The shrimp nips across to collect food from a little patch of algae
0:12:09 > 0:12:11that it knows is close to home.
0:12:22 > 0:12:26However, if the shrimp wanders too far there can be trouble.
0:12:28 > 0:12:32That was an anemone it blundered into and it beats a swift retreat.
0:12:38 > 0:12:40For a moment, it seems a little lost,
0:12:40 > 0:12:43but the faithful goby finds it
0:12:43 > 0:12:46and this devoted pair are soon reunited.
0:12:48 > 0:12:51This predator spells danger for both creatures.
0:12:53 > 0:12:55But the goby gives the signal
0:12:55 > 0:12:59and both grateful landlord and lodger retreat safely indoors.
0:12:59 > 0:13:03Happy with that - that's the rent sorted for another month!
0:13:11 > 0:13:16Sharing a home can lead to living on top of each other,
0:13:16 > 0:13:19but for some creatures, this can be a distinct advantage.
0:13:21 > 0:13:25One such animal lives in the rainforests of Latin America.
0:13:28 > 0:13:31The famously slow-moving sloth.
0:13:41 > 0:13:42Thanks to its damp fur,
0:13:42 > 0:13:47it is able to employ the help of a rarely celebrated organism - algae.
0:13:49 > 0:13:53It helps the sloth blend in to its green surroundings,
0:13:53 > 0:13:56providing it with a sort of living camouflage.
0:14:04 > 0:14:06And the partnerships don't end there.
0:14:06 > 0:14:09The nutritious algae attracts its own admirers -
0:14:09 > 0:14:13insects like these moths, who like to eat it.
0:14:19 > 0:14:22But the moths are welcome lodgers for the sloth
0:14:22 > 0:14:26as they too bring their own rather surprising benefits.
0:14:32 > 0:14:36Once a week, their sloth landlord sets off to the ground
0:14:36 > 0:14:39at a pace a snail would consider reckless.
0:14:42 > 0:14:46He does this for his weekly call of nature.
0:14:50 > 0:14:53The female moths take this opportunity to jump off
0:14:53 > 0:14:56and lay their eggs in the steaming dung.
0:15:02 > 0:15:05Some hop back on to their furry friend,
0:15:05 > 0:15:08bringing with them a lovely bit of sloth dung.
0:15:09 > 0:15:12It's the perfect fertiliser for the growing algae,
0:15:12 > 0:15:15helping to keep the sloth the right shade of green
0:15:15 > 0:15:18and hidden from predators.
0:15:18 > 0:15:19Perfect!
0:15:32 > 0:15:36Some animals go to quite extreme depths in their quest
0:15:36 > 0:15:38to find a secure place to lodge.
0:15:40 > 0:15:44A pearl fish is looking for exactly that - a hidey hole.
0:15:47 > 0:15:51This cumbersome oddball could be the answer.
0:15:53 > 0:15:56A rather strange looking lump known as a sea cucumber.
0:15:59 > 0:16:02It spends its days sucking sand in through one end of its body,
0:16:02 > 0:16:04extracting anything nutritious from it
0:16:04 > 0:16:08and passing what it doesn't want out the other end.
0:16:11 > 0:16:13It is the ultimate beachcomber.
0:16:13 > 0:16:18OK, it's revolting, but could this walking colon be a safe haven?
0:16:23 > 0:16:25It seems it could and, strangely,
0:16:25 > 0:16:29it prefers the 'back door' to the front.
0:16:33 > 0:16:34Any port in a storm...!
0:16:41 > 0:16:44But the pearl fish is, in fact, very clever.
0:16:44 > 0:16:46Sea cucumbers are repulsive to most predators,
0:16:46 > 0:16:49meaning the crafty lodger is safe inside.
0:16:53 > 0:16:56In fact, it is such a comfortable pad that, after settling in,
0:16:56 > 0:16:59it is happy to share its home with friends and family.
0:17:11 > 0:17:13Now, time for a breath of fresh air!
0:17:17 > 0:17:18Whether invited or not,
0:17:18 > 0:17:22partnerships can involve all kinds of diverse creatures.
0:17:25 > 0:17:30Some of these creatures pair up not with animals, but with plants.
0:17:42 > 0:17:47In Madagascar, the baobab tree is regularly pollinated
0:17:47 > 0:17:49by the giant hawk moth.
0:18:01 > 0:18:05But the tree also plays host to another creature,
0:18:05 > 0:18:06one which will kill a moth.
0:18:13 > 0:18:14The mouse lemur,
0:18:14 > 0:18:17one of the world's smallest primates.
0:18:26 > 0:18:29He drinks the sweet nectar from the tree's flowers.
0:18:31 > 0:18:34It's packed with sugary energy.
0:18:44 > 0:18:48But he particularly enjoys a meal of moth.
0:19:03 > 0:19:06It seems the lemur is doing the baobab no favours
0:19:06 > 0:19:10by killing its moth pollinator but, without knowing it,
0:19:10 > 0:19:13this mini assassin is actually performing the same role.
0:19:15 > 0:19:18As he wrestles with the moth, his fur becomes dusted with pollen.
0:19:24 > 0:19:27Later, as he moves from tree to tree,
0:19:27 > 0:19:32this will spread across the forest, helping other baobabs to grow.
0:19:34 > 0:19:39So, in this relationship, the baobab is surprisingly the ultimate winner.
0:19:53 > 0:19:55On the other side of the world
0:19:55 > 0:19:58is a partnership which has knock-on benefits
0:19:58 > 0:20:00for the most unlikely of candidates.
0:20:03 > 0:20:05This Sundarbans in southern Asia
0:20:05 > 0:20:09are the largest tidal mangrove forests in the world.
0:20:12 > 0:20:14And a tiger reserve.
0:20:28 > 0:20:31Mangroves are the only trees that can exist in salty water.
0:20:33 > 0:20:37They have roots which stick up like snorkels sucking in oxygen
0:20:37 > 0:20:40as they can't get enough out of the thick mud.
0:20:42 > 0:20:45But mangroves need more than this to thrive.
0:20:47 > 0:20:50Luckily, they have found an ideal partner.
0:20:55 > 0:20:58One which can only be seen at low tide.
0:21:02 > 0:21:03Millions of crabs.
0:21:06 > 0:21:10Leaf-eating crabs and fiddler crabs.
0:21:10 > 0:21:12They make their homes here.
0:21:12 > 0:21:14It's an ideal place for them
0:21:14 > 0:21:17to create their labyrinth of underground tunnels.
0:21:22 > 0:21:25The tunnels are vital for the mangroves.
0:21:25 > 0:21:28At low tide they channel air through the mud.
0:21:33 > 0:21:36Also, crabs help nourish the trees.
0:21:38 > 0:21:41The fiddlers recycle the bacteria-rich mud,
0:21:41 > 0:21:43releasing nutrients for the roots.
0:21:53 > 0:21:55While, as their name suggests,
0:21:55 > 0:21:59the leaf-eaters gather up and digest the mangroves' leaves,
0:21:59 > 0:22:02producing their own natural fertiliser.
0:22:06 > 0:22:09The crabs' burrows even help control the saltiness of the swamp.
0:22:09 > 0:22:14When mangroves take up water, they leave the salt behind.
0:22:14 > 0:22:18As the tide comes in, fresh seawater floods the crabs' burrows
0:22:18 > 0:22:20and dilutes the salty remains.
0:22:27 > 0:22:31Less toxic mud allows the mangroves to flourish.
0:22:37 > 0:22:41Without their crab partners, the Sundarbans just couldn't survive
0:22:41 > 0:22:43and without the Sundarbans,
0:22:43 > 0:22:45the tigers here would also be in trouble.
0:22:47 > 0:22:51Crabs helping to secure the future of a tiger?
0:22:51 > 0:22:55You have to admire these sideways eco-warriors.
0:23:05 > 0:23:08Protection is paramount in the endless battleground
0:23:08 > 0:23:10that is the natural world.
0:23:11 > 0:23:15It could be a crucial warning call in return for titbits...
0:23:15 > 0:23:17BIRD CHEEPS
0:23:17 > 0:23:21..but it always pays to have someone to watch your back.
0:23:24 > 0:23:28Surprisingly, though, this protective friend
0:23:28 > 0:23:31can sometimes be a creature you'd expect to be your archenemy.
0:23:54 > 0:23:58Normally, this venomous tarantula would eat a small toad,
0:23:58 > 0:24:02but here it is welcomed into the protection of its lair.
0:24:05 > 0:24:08It's not a personal thing, it's purely business.
0:24:08 > 0:24:10The toad offers a useful service.
0:24:12 > 0:24:14Pest control.
0:24:15 > 0:24:19The spider's egg sacs are infested with insects,
0:24:19 > 0:24:21which the toad soon makes a meal of.
0:24:40 > 0:24:42In return for getting rid of the ants,
0:24:42 > 0:24:45the tarantula offers very effective security.
0:24:48 > 0:24:50Screech owls enjoy a dinner of toad,
0:24:50 > 0:24:53which would normally be easy pickings.
0:24:55 > 0:24:59But the spider unleashes a barrage of barbed hairs.
0:25:02 > 0:25:07Like tiny vicious arrows, they soon discourage the unwelcome intruder.
0:25:28 > 0:25:32The coral reef, thriving metropolis of the ocean.
0:25:32 > 0:25:35With such a rich and diverse habitat,
0:25:35 > 0:25:38no wonder so many remarkable partnerships have evolved.
0:25:42 > 0:25:45These small, defenceless clownfish
0:25:45 > 0:25:48seem to have picked a tough place to live,
0:25:48 > 0:25:51amongst the tentacles of a sea anemone.
0:25:53 > 0:25:56The anemone is armed with paralysing stings -
0:25:56 > 0:25:58stings that can kill a fish.
0:26:00 > 0:26:02To avoid this fate,
0:26:02 > 0:26:06the clownfish dance deftly among the stinging tentacles.
0:26:13 > 0:26:14They produce a special mucus
0:26:14 > 0:26:17which, ultimately, stops the stings from firing.
0:26:23 > 0:26:26Very quickly, the clownfish are immune.
0:26:30 > 0:26:34They've effectively found themselves a security partner
0:26:34 > 0:26:38and turned the anemone into their very own fortress.
0:26:38 > 0:26:41It's an ideal one for them to lay their eggs.
0:26:45 > 0:26:49In return, the constant movement of the fish
0:26:49 > 0:26:54helps oxygenate the sea anemone - a perfect reciprocal arrangement.
0:27:06 > 0:27:07Keeping safe and secure
0:27:07 > 0:27:11can be all about choosing the right kind of neighbour.
0:27:17 > 0:27:18These burrowing owls
0:27:18 > 0:27:22have chosen to move into a large estate in North America
0:27:22 > 0:27:24known as 'Dog Town'.
0:27:26 > 0:27:29It's a huge area of underground tunnels
0:27:29 > 0:27:33built by a community of prairie dogs.
0:27:42 > 0:27:46The owls have chosen this rather rough-looking area
0:27:46 > 0:27:49as it has a well organised neighbourhood watch scheme.
0:27:57 > 0:28:03The prairie dogs provide a free and very sophisticated security system.
0:28:06 > 0:28:10Members of their community take it in turns to watch out for predators.
0:28:13 > 0:28:17The lookout guard has different calls for different threats,
0:28:17 > 0:28:20threats to both the dogs and the owls.
0:28:24 > 0:28:26PRAIRIE DOG CHIRPS
0:28:39 > 0:28:41PRAIRIE DOG CHIRPS
0:28:46 > 0:28:48CHIRPING
0:28:52 > 0:28:54The wise owl may be a myth,
0:28:54 > 0:28:58but these earthbound head-turners are a savvy bunch.
0:29:11 > 0:29:14At times, survival can depend on taking opportunities
0:29:14 > 0:29:16when they come along.
0:29:16 > 0:29:20Some creatures are better at exploiting them than others
0:29:20 > 0:29:24and often it's a case of how sneaky you're prepared to be.
0:29:43 > 0:29:47These capuchins live in one of Brazil's most extreme landscapes,
0:29:47 > 0:29:49where food is hard to come by.
0:29:55 > 0:29:57So they have had to have learn to be very resourceful.
0:30:06 > 0:30:08They have spotted a yellow rat snake,
0:30:08 > 0:30:12a creature which can be dangerous for young capuchins.
0:30:20 > 0:30:22The capuchins all work together,
0:30:22 > 0:30:25trying to make as much noise as possible to scare off the snake.
0:30:43 > 0:30:47Then they realise the snake offers an opportunity.
0:30:47 > 0:30:51It has found a Brazilian rodent called a punare -
0:30:51 > 0:30:54a potential meal for both snakes and capuchins.
0:31:02 > 0:31:04The punare has nowhere to hide.
0:31:18 > 0:31:22Very soon, the silent hunting technique of the snake has paid off.
0:31:30 > 0:31:34Then, one of the capuchins attempts something rather risky.
0:31:37 > 0:31:40With hundreds of backwards-facing teeth,
0:31:40 > 0:31:43the snake is not going to give up prey easily.
0:31:51 > 0:31:53It was worth a go.
0:31:57 > 0:31:59But the snake has created an opportunity
0:31:59 > 0:32:01for the quick-witted capuchins.
0:32:07 > 0:32:09There's more than one rodent up for grabs here.
0:32:16 > 0:32:19The most experienced male takes the lead.
0:32:26 > 0:32:27Got it!
0:32:42 > 0:32:44With a little help from the snake,
0:32:44 > 0:32:47the capuchins have cleverly scrounged themselves a meal.
0:32:59 > 0:33:03Sneakily scrounging from other animals is a smart move
0:33:03 > 0:33:06and some creatures have become expert at it.
0:33:14 > 0:33:18Cowbirds have latched on to a much larger animal than themselves.
0:33:22 > 0:33:25They do so because the movement the bison make
0:33:25 > 0:33:29stir up hundreds of insects, which the birds eat.
0:33:31 > 0:33:34A good roll in the dust throws up a decent meal,
0:33:34 > 0:33:38but the tiny birds also know when to keep out of the way.
0:33:42 > 0:33:47Just as well, as the males can get quite excited and aggressive.
0:33:56 > 0:34:00Living close by and scrounging from these big beasts
0:34:00 > 0:34:02helps guarantee the birds' survival.
0:34:09 > 0:34:12When the bison migrate, the birds will follow.
0:34:15 > 0:34:19These little birds even lay their eggs in other birds' nests,
0:34:19 > 0:34:22so their chicks are unwittingly brought up by others.
0:34:25 > 0:34:29They do this so they are not left behind when the bison move on.
0:34:29 > 0:34:31You have got to hand it to them,
0:34:31 > 0:34:34these birds are more than just a bit sneaky, they're ruthless.
0:34:50 > 0:34:55In the icy forests of the Arctic, are two very cunning scroungers
0:34:55 > 0:34:58that have, surprisingly, learned to work together.
0:35:06 > 0:35:09RAVEN CALLS OUT
0:35:13 > 0:35:18In this bitterly cold landscape, a raven calls out.
0:35:18 > 0:35:21RAVEN CALLS OUT
0:35:21 > 0:35:27It's found its dinner, but it needs another animal's help to enjoy it.
0:35:27 > 0:35:28The wolverine.
0:35:39 > 0:35:44The raven, a highly intelligent bird, directs the ravenous wolverine
0:35:44 > 0:35:46to the moose carcass it's found.
0:36:00 > 0:36:06The moose is frozen solid - too hard for the raven to break through.
0:36:14 > 0:36:16The wolverine's powerful jaws
0:36:16 > 0:36:21make short work of this frozen ready meal, exposing the softer middle.
0:36:26 > 0:36:31The raven will have to wait until its partner has had its fill.
0:36:39 > 0:36:43But it knows that patience will eventually pay off.
0:37:02 > 0:37:06The wolverine drags a chunk of the carcass off into the forest.
0:37:13 > 0:37:16But there are plenty of scraps left for the raven.
0:37:20 > 0:37:21And its friends.
0:37:42 > 0:37:48What the wolverine can't manage it will bury for a later date.
0:37:49 > 0:37:53It's always useful to have extra food in the freezer!
0:38:04 > 0:38:06In the struggle for survival,
0:38:06 > 0:38:09cooperation with a completely different species
0:38:09 > 0:38:12can be a way of gaining a crucial advantage,
0:38:12 > 0:38:15but some animals have learned that working together
0:38:15 > 0:38:18within their own family is the key to success.
0:38:38 > 0:38:42Elephants live in large groups with strong social bonds.
0:38:44 > 0:38:46This large herd in Kenya
0:38:46 > 0:38:49is made up of several females and their offspring.
0:38:51 > 0:38:56Amongst the herd is an inexperienced mother with a newborn calf.
0:39:07 > 0:39:09She couldn't keep up with the herd,
0:39:09 > 0:39:13but the grandmother of the calf has stayed behind to help.
0:39:23 > 0:39:25Meanwhile, the rest of the herd reach the river.
0:39:27 > 0:39:31The older calves are unceremoniously encouraged to take the plunge.
0:39:33 > 0:39:35You could call it tough love.
0:39:40 > 0:39:42In her effort to catch up with the others,
0:39:42 > 0:39:46the new mother leads her baby across a slippery mud pan.
0:40:07 > 0:40:10It's not the best route for a newborn.
0:40:22 > 0:40:25Grandmother steps in to try and help guide the calf across.
0:40:49 > 0:40:51Having finally reached the river,
0:40:51 > 0:40:54the young mother again chooses a difficult route for her baby.
0:41:15 > 0:41:20Oh, dear. He's now blocked by what, for him, is an impossibly high bank.
0:41:23 > 0:41:26But this is where being part of a family pays off.
0:41:26 > 0:41:30The herd see that he's struggling and return to try to help him.
0:41:32 > 0:41:34Everyone gets involved in the rescue,
0:41:34 > 0:41:36all trying to save the newborn.
0:41:57 > 0:42:01They've done it, thanks to the family working together.
0:42:12 > 0:42:16Strong partnerships in this herd will help the inexperienced mother
0:42:16 > 0:42:20become better at caring for her calf, giving both a brighter future.
0:42:26 > 0:42:28Working together in family groups
0:42:28 > 0:42:31is essential to the survival of so many different species.
0:42:39 > 0:42:43There's one animal which is famous for its impeccable teamwork.
0:42:47 > 0:42:51Ants function like a highly-disciplined army.
0:42:51 > 0:42:55Each is clear about its own role and they all work for the same goal.
0:43:00 > 0:43:03Nowhere is this teamwork more important
0:43:03 > 0:43:05than in the scorching heat of the desert.
0:43:07 > 0:43:09In the midday African sun,
0:43:09 > 0:43:13very little can survive the soaring temperatures.
0:43:13 > 0:43:17But these silver ants have special armoured skin which reflects light.
0:43:21 > 0:43:25They can tolerate temperatures that would kill any other land animal.
0:43:29 > 0:43:32But even they can only survive out here for a few minutes.
0:43:36 > 0:43:38They are in a race to find food
0:43:38 > 0:43:41while their predators have gone to ground.
0:43:47 > 0:43:49Only by working together as a team
0:43:49 > 0:43:51do the ants stand a chance of success.
0:44:04 > 0:44:07They've found a victim of heat stroke.
0:44:07 > 0:44:08A potential meal.
0:44:14 > 0:44:16But will they be able to get it home
0:44:16 > 0:44:18before being scorched themselves?
0:44:21 > 0:44:23They are nearing their maximum temperature.
0:44:23 > 0:44:26A blistering 53 degrees Celsius.
0:44:39 > 0:44:41Some can no longer take the heat.
0:44:50 > 0:44:52They're running out of time.
0:44:52 > 0:44:56They won't make it, not unless they can do something drastic.
0:45:13 > 0:45:15By biting off the legs and antennae,
0:45:15 > 0:45:19the ants stand a better chance of getting their prey back to the nest.
0:45:26 > 0:45:28With a final push, they've made it.
0:45:31 > 0:45:34Sacrifices were made along the way,
0:45:34 > 0:45:36but the team fulfilled their mission.
0:45:47 > 0:45:52From an army of ants to nature's own special forces.
0:45:54 > 0:45:58One of the most tactically advanced family partnerships
0:45:58 > 0:46:01in the natural world can be found in the sea.
0:46:03 > 0:46:04Killer whales.
0:46:07 > 0:46:11The ocean's apex predator takes teamwork
0:46:11 > 0:46:13and problem-solving to a whole new level.
0:46:16 > 0:46:18They employ a range of hunting strategies,
0:46:18 > 0:46:20demonstrating high intelligence.
0:46:32 > 0:46:36In the Antarctic, a pod of killer whales stays close together
0:46:36 > 0:46:38as they scour the sea looking for prey.
0:46:53 > 0:46:56There are several potential victims here.
0:47:06 > 0:47:08Although they are out of reach.
0:47:12 > 0:47:15The solution is highly complex teamwork.
0:47:17 > 0:47:21Swimming in perfect formation, they flick their tails in unison
0:47:21 > 0:47:24and create a wave that cracks the ice.
0:47:32 > 0:47:35They regroup and assess the damage.
0:47:37 > 0:47:39A more powerful wave is needed.
0:47:46 > 0:47:48With the ice floe breaking up,
0:47:48 > 0:47:51they can get a better look at their target.
0:47:53 > 0:47:57It's a crabeater seal. Quite vicious. Not their favourite.
0:48:08 > 0:48:11A Weddell seal is far more manageable.
0:48:24 > 0:48:28They unleash a powerful wave with remarkable accuracy.
0:48:40 > 0:48:43The seal is now where the killers want it.
0:48:44 > 0:48:47But there's still work to be done.
0:48:47 > 0:48:49They need to grab their prey by the tail,
0:48:49 > 0:48:51while avoiding its snapping jaws.
0:48:53 > 0:48:56Only then will they be able to pull it down and drown it.
0:48:58 > 0:49:02Side swipes create violent underwater turbulence, a new tactic.
0:49:11 > 0:49:14Blowing bubbles gives cover for others in the team
0:49:14 > 0:49:16to lunge at the seal's tail.
0:49:23 > 0:49:26Somehow, the seal manages to reach a tiny ice floe.
0:49:32 > 0:49:35The killers could easily grab it now.
0:49:35 > 0:49:38But rather like a cat with an injured mouse,
0:49:38 > 0:49:40they seem to be enjoying the sport.
0:50:00 > 0:50:03Yet again, the pod joins forces to dislodge the seal.
0:50:20 > 0:50:22Completely exhausted,
0:50:22 > 0:50:25the seal hardly has the energy left to pull itself to safety.
0:50:39 > 0:50:41For the unfortunate seal,
0:50:41 > 0:50:42it's game over...
0:50:50 > 0:50:52..falling victim to, without doubt,
0:50:52 > 0:50:55one of nature's most lethal partnerships.
0:51:11 > 0:51:13Throughout history,
0:51:13 > 0:51:16partnerships have also existed between animals and humans.
0:51:19 > 0:51:23The majority of these are rather one-sided,
0:51:23 > 0:51:26with humans harnessing the skills of wild animals for their own ends.
0:51:32 > 0:51:34However, some special relationships do exist
0:51:34 > 0:51:37where an understanding between animal and human
0:51:37 > 0:51:40has developed which is quite extraordinary.
0:51:54 > 0:51:58Bottlenose dolphins make their way to a shoreline in Brazil.
0:52:03 > 0:52:05They have forged a remarkable partnership
0:52:05 > 0:52:07with the local fishermen here.
0:52:11 > 0:52:14Large numbers of mullet come through this area in the early summer.
0:52:19 > 0:52:22The problem for the fishermen is that the water is so murky
0:52:22 > 0:52:23they can't see where to cast their nets.
0:52:28 > 0:52:32The dolphins drive the mullet towards the fishermen
0:52:32 > 0:52:36and even signal when to cast their nets with their distinctive dives.
0:52:46 > 0:52:49The fishermen claim they can even tell the size of the school
0:52:49 > 0:52:51and which way it is travelling
0:52:51 > 0:52:53by the vigour and direction of the dive.
0:52:57 > 0:53:00The dolphins do all the hard work herding the mullet,
0:53:00 > 0:53:02much to the joy of the fishermen.
0:53:08 > 0:53:11They can catch many kilos of fish in this way.
0:53:23 > 0:53:27The dolphins have no trouble rounding up shoals of fish,
0:53:27 > 0:53:30but picking off individuals is more difficult for them.
0:53:36 > 0:53:39It's here they benefit from their fellow fishermen.
0:53:40 > 0:53:42The nets panic the mullet,
0:53:42 > 0:53:44forcing them to break formation.
0:53:44 > 0:53:46As the fish make their bid for freedom,
0:53:46 > 0:53:48the dolphins seize their chance.
0:53:53 > 0:53:56And they're not the only ones to benefit.
0:54:06 > 0:54:09One of the most extraordinary partnerships between humans
0:54:09 > 0:54:12and wild animals can be found in East Africa.
0:54:13 > 0:54:16It's a unique relationship,
0:54:16 > 0:54:18which can be traced right back to the 17th century.
0:54:21 > 0:54:24This honeyguide bird is calling out...
0:54:28 > 0:54:31..not to other birds, but amazingly, to humans.
0:54:34 > 0:54:38Its intention is to lead a couple of local Masai to a beehive.
0:54:40 > 0:54:43Thanks to its acute sense of smell, it's already found the hive,
0:54:43 > 0:54:47but without human help it would find it much harder to reach
0:54:47 > 0:54:49the sweet honeycomb inside.
0:55:10 > 0:55:12It becomes a game of follow my leader.
0:55:30 > 0:55:33As the honeyguide gets closer to the prize,
0:55:33 > 0:55:37it changes its call to let them know they're getting warmer.
0:55:47 > 0:55:49Here it is,
0:55:49 > 0:55:51a hive well-hidden in a tree
0:55:51 > 0:55:53and covered by hundreds of African bees.
0:55:59 > 0:56:02The boys use smoke to help calm the bees.
0:56:02 > 0:56:05Without this smoke, it would be much more painful for either the locals
0:56:05 > 0:56:07or the bird to get to the honeycomb.
0:56:30 > 0:56:33The honeyguide bird is the only wild animal
0:56:33 > 0:56:36known to actually guide people to food in this remarkable way.
0:56:43 > 0:56:48These Masai know it's important to keep up their part of the bargain.
0:56:48 > 0:56:51The honeyguide bird is rewarded with its share.
0:56:59 > 0:57:02A guarantee that this unique partnership can continue.
0:57:15 > 0:57:18It's a measure of the huge diversity
0:57:18 > 0:57:20and enduring mystery of the natural world
0:57:20 > 0:57:24that these extraordinary animal partnerships exist.
0:57:27 > 0:57:30I mean, who would've thought it, a bird helping out a tortoise...
0:57:37 > 0:57:40..never mind a raven sharing dinner with a wolverine?
0:57:45 > 0:57:48It seems these relationships are all about survival.
0:57:50 > 0:57:52And without doubt,
0:57:52 > 0:57:56having a partner, some more perfect than others,
0:57:56 > 0:57:58can make all the difference.