0:00:05 > 0:00:09You and I belong to an extraordinary family.
0:00:15 > 0:00:18A family of hundreds of bizarre,
0:00:18 > 0:00:20colourful
0:00:20 > 0:00:22and characterful animals...
0:00:24 > 0:00:27I don't think I've seen anything quite like this in my whole life!
0:00:29 > 0:00:31..who lead fascinating
0:00:31 > 0:00:33and dramatic lives,
0:00:33 > 0:00:35all over the world.
0:00:38 > 0:00:40We - that is monkeys,
0:00:40 > 0:00:42lemurs
0:00:42 > 0:00:44and apes -
0:00:44 > 0:00:46are all primates.
0:00:46 > 0:00:51And I want to introduce you to this amazing animal family.
0:00:53 > 0:00:57To meet some relatives you never even knew you had.
0:01:25 > 0:01:27The jungles of Borneo are home
0:01:27 > 0:01:30to some of the most unusual primates on the planet.
0:01:38 > 0:01:40Strange monkeys.
0:01:42 > 0:01:44Poisonous lorises.
0:01:47 > 0:01:50And our closest cousins - the great apes.
0:02:02 > 0:02:06Orangutans normally spend their lives high in the tree tops.
0:02:09 > 0:02:11But there is one community
0:02:11 > 0:02:14that's unlike any other group of wild apes on Earth.
0:02:21 > 0:02:25They've begun to behave in a way that's almost human.
0:02:40 > 0:02:44This has got to be about one of the most bizarre things
0:02:44 > 0:02:46I've ever experienced.
0:02:51 > 0:02:54These aren't captive animals trained to do tricks.
0:02:57 > 0:03:00They're free-living orangutans,
0:03:00 > 0:03:04who've adopted an unusual way of life.
0:03:09 > 0:03:13And of all the orangutans here, Siswi is the most unusual.
0:03:19 > 0:03:22Aahhh! Thanks, Siswi(!)
0:03:22 > 0:03:27This has got to be the cleanest orangutan in the whole of Borneo!
0:03:32 > 0:03:35Siswi and I are two of roughly 400 species
0:03:35 > 0:03:38of primate in the world,
0:03:38 > 0:03:41and although we all look very different,
0:03:41 > 0:03:44we share certain features that make us part
0:03:44 > 0:03:47of one of the most extraordinary families on Earth.
0:03:49 > 0:03:52It's one of these shared features - our intelligence -
0:03:52 > 0:03:55that helps explain this curious behaviour.
0:03:58 > 0:04:01Here orangutans and humans share the same forest.
0:04:04 > 0:04:06They've watched us.
0:04:08 > 0:04:11And begun to experiment with what they've seen.
0:04:19 > 0:04:21This may look a bit bizarre,
0:04:21 > 0:04:24but it actually shows how smart she is.
0:04:24 > 0:04:27She's seen humans here every morning, washing,
0:04:27 > 0:04:30and she's basically doing exactly the same.
0:04:34 > 0:04:37We also share a similar face.
0:04:37 > 0:04:39Our eyes face forwards.
0:04:41 > 0:04:44This gives us the ability to judge distances perfectly.
0:04:46 > 0:04:49And there's one more similarity.
0:04:49 > 0:04:53Critically, we have this amazing hand with a thumb that can fold over
0:04:53 > 0:04:57and that is probably the most defining characteristic
0:04:57 > 0:04:58of any primate.
0:05:02 > 0:05:06Intelligence, binocular vision and a dexterous hand
0:05:06 > 0:05:10allow these orangutans to behave so much like us.
0:05:12 > 0:05:15They are the three things we all have in common.
0:05:18 > 0:05:22But that certainly doesn't mean all primates look similar.
0:05:30 > 0:05:35The tarsier is 400 times smaller than an orangutan.
0:05:37 > 0:05:41It also has forward-facing eyes,
0:05:41 > 0:05:43a dextrous hand,
0:05:43 > 0:05:45and intelligence,
0:05:45 > 0:05:48but it uses them in a completely different way.
0:06:02 > 0:06:08This tennis ball-sized gremlin is a spring-loaded ambush predator.
0:06:12 > 0:06:16Long back legs can propel it up to 40 times its body length.
0:06:20 > 0:06:24Its huge eyes are bigger than its stomach,
0:06:24 > 0:06:27and gather every scrap of light.
0:06:27 > 0:06:29They're too large to move in their sockets,
0:06:29 > 0:06:35but the tarsier can swivel its head through almost 360 degrees.
0:06:39 > 0:06:44And when it can't see its prey, it uses ultrasonic hearing.
0:06:47 > 0:06:53Those satellite-dish ears pinpoint rustles that we humans cannot hear.
0:07:28 > 0:07:34Evolution has moulded the tarsier into a ruthlessly efficient hunter.
0:07:34 > 0:07:36The most carnivorous of all primates.
0:07:47 > 0:07:50We humans have got some pretty bizarre cousins,
0:07:50 > 0:07:53but primates don't just live in jungles like the tarsier
0:07:53 > 0:07:55or the orangutan.
0:07:55 > 0:07:58In fact, we've got relatives right across the planet,
0:07:58 > 0:08:01and some of them have managed to scrape a living
0:08:01 > 0:08:04in the most unexpected of places.
0:08:11 > 0:08:13Away from the tropics,
0:08:13 > 0:08:15life is very different indeed.
0:08:31 > 0:08:35Japanese macaques live further north than any other monkey.
0:08:36 > 0:08:39Right on the edge of what is possible.
0:08:44 > 0:08:48Here, temperatures can hit minus 20 degrees Celsius.
0:08:51 > 0:08:55The secret to surviving when the temperature's this low
0:08:55 > 0:08:58is to have lots of layers -
0:08:58 > 0:09:01layers are really important because they trap warm air
0:09:01 > 0:09:04next to your skin.
0:09:05 > 0:09:09With a thermal camera, I can show you just how much heat you lose
0:09:09 > 0:09:12without those protective layers.
0:09:19 > 0:09:22The first thing to go are my feet,
0:09:22 > 0:09:26they're feeling very, very cold now.
0:09:31 > 0:09:35Only five minutes later, my core temperature is dangerously low.
0:09:41 > 0:09:45Eventually I would enter a coma from which I would never wake up.
0:10:01 > 0:10:05To live in a sub-zero world you have to be built for it.
0:10:08 > 0:10:11These snow monkeys have two distinct layers of fur
0:10:11 > 0:10:14that trap warm air next to their skin.
0:10:17 > 0:10:22While their short tails and stumpy ears reduce the chance of frostbite.
0:10:29 > 0:10:33Food is extremely hard to come by and the monkeys lose almost
0:10:33 > 0:10:36a quarter of their body weight throughout the winter.
0:10:42 > 0:10:45Snow monkeys might be built for the cold,
0:10:45 > 0:10:48but as the temperatures plummet after dark,
0:10:48 > 0:10:50they have to find other ways to keep warm,
0:10:50 > 0:10:53and they do this in a rather remarkable way.
0:11:08 > 0:11:11For a small monkey, thick fur isn't enough to stay warm
0:11:11 > 0:11:14in these sub-zero conditions.
0:11:24 > 0:11:28For the first time ever, we have a privileged insight
0:11:28 > 0:11:32into how these incredible monkeys stay alive.
0:11:39 > 0:11:43As they climb the trees one monkey is joined by another,
0:11:45 > 0:11:49then another
0:11:49 > 0:11:52and another.
0:11:55 > 0:11:58A single monkey would freeze to death out here,
0:11:58 > 0:12:02but by huddling, the macaques form a giant super-monkey -
0:12:02 > 0:12:06one so big that it creates a microclimate of its own.
0:12:10 > 0:12:12As a baby settles down for the night
0:12:12 > 0:12:15the intense glow of heat shows just how toasty
0:12:15 > 0:12:18it must be at the heart of the huddle.
0:12:21 > 0:12:25Throughout the night, the monkeys take it in turns in the hotspot.
0:12:34 > 0:12:38Dawn, and the snow monkeys are snuggled up tighter than ever.
0:12:47 > 0:12:50We've all been there, wrapped up in a warm duvet
0:12:50 > 0:12:52on a cold, chilly morning.
0:12:54 > 0:12:56And thanks to that huddle,
0:12:56 > 0:13:00these resourceful monkeys have beaten the elements.
0:13:11 > 0:13:13Well, it was pretty cold last night,
0:13:13 > 0:13:15and if I, or indeed most other primates,
0:13:15 > 0:13:19had been out here on their own, we would have perished hours ago.
0:13:22 > 0:13:24In the extremes of the primate world,
0:13:24 > 0:13:26it's teamwork like this
0:13:26 > 0:13:29that makes the difference between life and death.
0:13:42 > 0:13:46The spiny forest of Madagascar is at the other extreme -
0:13:46 > 0:13:50one of the hottest and driest forests on Earth.
0:13:53 > 0:13:56The temperatures here can exceed 40 degrees,
0:13:56 > 0:13:59and it doesn't rain for months on end.
0:14:09 > 0:14:14The few plants that grow here are protected by rapier-like thorns.
0:14:23 > 0:14:25But sifakas spend their lives
0:14:25 > 0:14:27in this forest of spines.
0:14:36 > 0:14:39These adrenaline junkies risk life and limb every day.
0:14:55 > 0:14:57Their binocular vision allows them
0:14:57 > 0:15:00to pick landing spots with unerring accuracy.
0:15:02 > 0:15:05And long back legs can catapult them
0:15:05 > 0:15:07nine metres in a single leap.
0:15:16 > 0:15:20Though how they avoid getting cut to pieces is still a mystery.
0:15:23 > 0:15:27The prize for these hardy lemurs is lots of succulent leaves,
0:15:27 > 0:15:29full of precious water -
0:15:31 > 0:15:33quenching their thirst
0:15:33 > 0:15:36in the blistering heat.
0:15:54 > 0:15:58Heat is just one problem for the most southerly monkey in the world.
0:16:07 > 0:16:08Chacma baboons
0:16:08 > 0:16:12live in the raw, exposed South African Cape.
0:16:15 > 0:16:18SHORT GRUNTING SOUNDS
0:16:20 > 0:16:23Here there's virtually no protection from the elements.
0:16:25 > 0:16:26Battered by winds,
0:16:26 > 0:16:30they scratch a living under the intense glare of the midday sun.
0:16:36 > 0:16:38These baboons have a hard life.
0:16:38 > 0:16:41By midday, it's blisteringly hot
0:16:41 > 0:16:45and they have to spend hours roaming to find enough food,
0:16:45 > 0:16:49but their real problem is finding somewhere safe to sleep.
0:16:49 > 0:16:52MAKES NO SOUND
0:16:54 > 0:16:58At night, leopards roam these plains
0:16:58 > 0:17:00and with very few trees to hide in,
0:17:00 > 0:17:04the troop are exposed to the biggest danger of all -
0:17:04 > 0:17:06being eaten.
0:17:11 > 0:17:14To avoid this, their choice of dormitory
0:17:14 > 0:17:17is one of the most bizarre in the primate world.
0:17:23 > 0:17:25Here it is. Look.
0:17:29 > 0:17:32This small hole is the entrance to a cave.
0:17:35 > 0:17:39It's incredibly rare for any primate to use a cave,
0:17:39 > 0:17:41so while the baboons are out hunting for food,
0:17:41 > 0:17:44I'm going to get some kit on
0:17:44 > 0:17:47and go down and see what their sleeping accommodation is all about.
0:17:55 > 0:17:57This is a high security location.
0:18:01 > 0:18:03There are bees at the entrance
0:18:03 > 0:18:06and an eight-metre vertical drop.
0:18:26 > 0:18:28Well, everywhere you look
0:18:28 > 0:18:32there's evidence of habitual use of this cave by baboons.
0:18:32 > 0:18:35There's bones everywhere, remains...
0:18:35 > 0:18:38There's dung - some of it not so old, I can tell you!
0:18:38 > 0:18:40Some pretty fresh stuff.
0:18:44 > 0:18:46I'm now 100 metres underground
0:18:47 > 0:18:50and it hasn't been easy for me,
0:18:50 > 0:18:53but for the baboons it must be 10 times harder,
0:18:53 > 0:18:57because they have to do it in complete darkness.
0:19:02 > 0:19:04BABOONS GROWL AND "BARK"
0:19:06 > 0:19:08As night falls, the baboons are clearly on edge.
0:19:12 > 0:19:15"BARKS"
0:19:15 > 0:19:18"BARKING" CONTINUES
0:19:20 > 0:19:23With the threat of an attack a very real possibility,
0:19:23 > 0:19:26the cave is an inviting prospect.
0:19:43 > 0:19:48An old rope left by bat researchers makes their descent easier.
0:19:54 > 0:19:58In the pitch black, the baboons can't see a thing,
0:19:58 > 0:20:02but our cameras reveal how they cope in this secret world.
0:20:02 > 0:20:04LOW "MURMURING"
0:20:06 > 0:20:10MONKEYS CHATTER
0:20:10 > 0:20:13The first thing they do is call to each other
0:20:13 > 0:20:15to work out where everyone is.
0:20:19 > 0:20:21Effectively blindfolded
0:20:21 > 0:20:24they feel their way through the inky blackness.
0:20:25 > 0:20:28MONKEYS GRUNT
0:20:35 > 0:20:39Amazingly, like you and I know our way around our house at night,
0:20:39 > 0:20:41the adults appear to have a mental map
0:20:41 > 0:20:45of the entire 100-metre cave system.
0:20:45 > 0:20:49GRUNTING
0:20:49 > 0:20:53But when you can't see who's around you, it's easy to get spooked.
0:20:53 > 0:21:01SCREECHING
0:21:01 > 0:21:07GRUNTING AND CHATTERING
0:21:07 > 0:21:11Spending your night underground might seem like an odd thing to do,
0:21:11 > 0:21:13but early man did exactly the same.
0:21:17 > 0:21:23THEY CHATTER AND SQUEAL
0:21:23 > 0:21:26Putting the kids to bed is never easy.
0:21:28 > 0:21:33And a cave like this provides plenty of space for some... private time.
0:21:46 > 0:21:49And eventually a safe and peaceful night's sleep.
0:22:00 > 0:22:03Apart from the obvious security benefits,
0:22:03 > 0:22:07getting the right sort of sleep could have other advantages.
0:22:12 > 0:22:16REM sleep, the state where you dream, allows a complex brain
0:22:16 > 0:22:19to repair and revitalise.
0:22:20 > 0:22:24And it's that much easier when you're safe underground.
0:22:29 > 0:22:33It's thought that sleeping in a cave could sharpen the mind.
0:22:36 > 0:22:40Which for the baboons would make life on the edge of Africa
0:22:40 > 0:22:42that much easier to deal with.
0:22:57 > 0:23:01Over the last 55 million years, primates have branched out
0:23:01 > 0:23:06across the globe, but the family's roots are deep within the jungle.
0:23:08 > 0:23:10It is really amazing up here.
0:23:10 > 0:23:11I mean, if you think about it,
0:23:11 > 0:23:14it makes sense making your home up in the trees.
0:23:14 > 0:23:17For one thing, all your enemies, things that would eat you,
0:23:17 > 0:23:21are on the forest floor generally, 30 metres below you,
0:23:21 > 0:23:24and there's just all kinds of things to eat up here,
0:23:24 > 0:23:25lots of food and fruit.
0:23:28 > 0:23:30Tropical forests are home to the greatest
0:23:30 > 0:23:32diversity of primates on earth.
0:23:36 > 0:23:41In fact, over 90% of all primates live in forests.
0:23:57 > 0:24:00But it's definitely not as easy up here as it looks.
0:24:00 > 0:24:02HE GROANS WITH EFFORT
0:24:03 > 0:24:05I mean, this is very difficult.
0:24:05 > 0:24:09For an animal my size who shouldn't really be up trees,
0:24:09 > 0:24:11this is actually very alarming.
0:24:15 > 0:24:18We humans may have lost our head for heights,
0:24:18 > 0:24:21but other primates have made the most of life
0:24:21 > 0:24:22in a vertical world.
0:24:44 > 0:24:47There are some incredible ways to move through the forest,
0:24:47 > 0:24:52but the true gymnasts of the canopy have got to be the gibbons.
0:24:52 > 0:24:55Their highly specialised arms allow them to fly through
0:24:55 > 0:24:58the tree tops at breakneck speed.
0:25:00 > 0:25:04But in Thailand, not all gibbons have had the chance to do that.
0:25:12 > 0:25:16Six month old Sherpa has never set foot outside a cage.
0:25:21 > 0:25:25But today, he and his family are being released into the wild.
0:25:31 > 0:25:34They're pioneers, returning to a forest where gibbons were
0:25:34 > 0:25:37hunted to extinction 30 years ago.
0:25:48 > 0:25:53And on a day like this, the big wide world is tantalisingly close.
0:26:11 > 0:26:15Sherpa's dad is the first out, and his mum follows.
0:26:21 > 0:26:24But for Sherpa, it's a bit more daunting.
0:26:38 > 0:26:39A little bit of reassurance,
0:26:39 > 0:26:42and it's time to make a huge leap of faith.
0:27:04 > 0:27:08A quick hug and, after a lifetime in captivity,
0:27:08 > 0:27:10our young explorer is free.
0:27:19 > 0:27:23Unlike a wild gibbon, Sherpa has no experience
0:27:23 > 0:27:25and a bit too much enthusiasm.
0:27:31 > 0:27:33MAKES HIGH, PIERCING NOISE
0:27:33 > 0:27:36These thorny branches are rattan.
0:27:43 > 0:27:46Sherpa is learning a painful, but very valuable lesson.
0:27:58 > 0:28:01When you're a young gibbon, practice makes perfect.
0:28:15 > 0:28:19By watching his parents, he'll soon pick up all the skills he needs.
0:28:24 > 0:28:26In terms of sheer acrobatics,
0:28:26 > 0:28:29there's nothing to touch a wild gibbon.
0:28:35 > 0:28:39That powerful brain makes hundreds of life-saving decisions
0:28:39 > 0:28:40in the blink of an eye.
0:28:47 > 0:28:51And a ball and socket joint in their wrists gives them flexibility
0:28:51 > 0:28:53to slingshot through the canopy.
0:28:53 > 0:28:55HOOTING NOISE
0:29:13 > 0:29:19SHORT CALLING SOUNDS
0:29:23 > 0:29:26BIRDS CHIRP
0:29:31 > 0:29:35The huge range of environments that primates live in
0:29:35 > 0:29:37have shaped how they look and behave.
0:29:41 > 0:29:45But their diversity is also driven by what they eat.
0:29:51 > 0:29:54The Semien Mountains of Ethiopia are home to one of the world's
0:29:54 > 0:29:56most vegetarian primates.
0:30:03 > 0:30:05Geladas.
0:30:12 > 0:30:17After a cold night in the mountains, dawn is a welcome relief.
0:30:19 > 0:30:21I love this row here, at the edge of the cliff, who are just
0:30:21 > 0:30:25warming up in the sun. They're really putting their heads back
0:30:25 > 0:30:27and exposing their chests.
0:30:32 > 0:30:36Once they've warmed up, geladas need a hearty breakfast.
0:30:40 > 0:30:42But as far as the eye can see,
0:30:42 > 0:30:46there's only one thing to eat for every single meal.
0:30:48 > 0:30:49Grass.
0:30:57 > 0:31:00Grass is extremely low in calories,
0:31:00 > 0:31:04so these hardy mountaineers have to eat huge amounts.
0:31:07 > 0:31:10MONKEY COUGHS
0:31:12 > 0:31:15Your average monkey feeds for about four hours a day,
0:31:15 > 0:31:19whereas your average gelada has to feed for up to 10 hours a day.
0:31:19 > 0:31:24If I was to suddenly adopt the grass-only gelada diet, I'd have to
0:31:24 > 0:31:28chew down 17 kilograms of grass every day.
0:31:43 > 0:31:47Geladas are built to make the most of their vegetarian diet.
0:31:50 > 0:31:55Of all the primates, geladas have one of the most useful thumbs,
0:31:55 > 0:31:57and they use it in a pincer-like movement
0:31:57 > 0:32:01to pick only the most nutritious shoots and seeds.
0:32:03 > 0:32:07Abrasive teeth grind up the coarse leaves just like a cow.
0:32:10 > 0:32:14And built-in cushions make the long hours sitting a bit more bearable.
0:32:26 > 0:32:31Geladas need to eat all day long simply to survive.
0:32:36 > 0:32:38But for the smallest monkey in the world,
0:32:38 > 0:32:43it's less about the quantity of food, and more about its quality.
0:33:05 > 0:33:08Pygmy marmosets weigh no more than an apple.
0:33:13 > 0:33:18Here in Ecuador, catching dinner can be hard work,
0:33:18 > 0:33:20but luckily, marmosets have a reliable back up.
0:33:24 > 0:33:29And to make the most of it, they have a unique set of tools.
0:33:31 > 0:33:35Claws, rather than fingernails, give them extra grip.
0:33:40 > 0:33:45And their chisel-like teeth cut neat holes in the tough tree bark.
0:33:51 > 0:33:54But it's not the bark they're after.
0:33:57 > 0:34:00It's the sugar-rich sap underneath.
0:34:08 > 0:34:12Packed with energy and essential minerals,
0:34:12 > 0:34:15sap makes up 75% of their diet.
0:34:27 > 0:34:30What's really incredible is the scale of their ambition.
0:34:34 > 0:34:37A tree like this may have several hundred holes.
0:34:38 > 0:34:41Food production on an industrial scale.
0:34:45 > 0:34:48Marmosets harvest their crop wisely,
0:34:48 > 0:34:51they never take too much and only allow the holes
0:34:51 > 0:34:53to close up when the yield drops.
0:35:01 > 0:35:0510,000 year ago, farming was the basis of our civilisation.
0:35:07 > 0:35:11But deep in the Amazon, these industrious little monkeys
0:35:11 > 0:35:14were already enjoying a civilized way of life.
0:35:28 > 0:35:32The more specialised your diet, the stranger you can look.
0:35:33 > 0:35:37And in a leafy corner of the United States, science is
0:35:37 > 0:35:41unravelling the feeding habits of the strangest primate of all.
0:35:44 > 0:35:47Well, it's a little after sunrise, but behind this door
0:35:47 > 0:35:52it's about sunset, and the animal in here is just waking up.
0:36:01 > 0:36:03RUSTLING
0:36:13 > 0:36:15LOUD SNIFFING
0:36:31 > 0:36:33Look at this.
0:36:34 > 0:36:37This is about the strangest animal I've ever seen.
0:36:37 > 0:36:40If you didn't know what it was and had to describe it,
0:36:40 > 0:36:43you'd say it had the ears of a bat, the teeth of a rodent,
0:36:43 > 0:36:46the hands of an alien.
0:36:46 > 0:36:50It's got a bushy, squirrel-like tail, and yet it's in the same group
0:36:50 > 0:36:53of animals as you and I, it's almost hard to believe.
0:36:55 > 0:36:59This almost mythical creature is from Madagascar.
0:36:59 > 0:37:01MAKES SHORT LIP-SMACKING SOUNDS
0:37:01 > 0:37:03She's an aye-aye called Ardrey.
0:37:05 > 0:37:07That is so cute.
0:37:08 > 0:37:11I hate to use the word cute, but they are cute.
0:37:14 > 0:37:16I think I'm in love with this animal.
0:37:22 > 0:37:25Aye-ayes spend the night hunting for grubs that live
0:37:25 > 0:37:27deep inside decaying branches.
0:37:32 > 0:37:34To work out where the grubs are hidden,
0:37:34 > 0:37:37they use that strange looking hand.
0:37:39 > 0:37:43Tapping the wood at up to 10 times a second.
0:37:43 > 0:37:45There she goes, she's tapping now.
0:37:49 > 0:37:50I can hear it.
0:37:54 > 0:37:58That's the most specialised primate hand in the whole world.
0:38:00 > 0:38:04Like sonar, the sound penetrates the depths of the branch,
0:38:04 > 0:38:09and a coded message is echoed back to those super-sensitive ears.
0:38:12 > 0:38:17When she finds a hollow spot, she starts to dig.
0:38:17 > 0:38:21These incredibly sharp front teeth, the incisors, which unusually
0:38:21 > 0:38:23for primates continue to grow,
0:38:23 > 0:38:27and they rip the wood apart to get access to the cavity
0:38:27 > 0:38:30which might contain an insect larvae.
0:38:30 > 0:38:35The hearing is very acute so they can hear the larva inside.
0:38:42 > 0:38:45But it's her probe-like middle finger that has
0:38:45 > 0:38:46to find the grub.
0:38:48 > 0:38:52And the latest science is now revealing just how incredible
0:38:52 > 0:38:54this unique digit is.
0:38:59 > 0:39:01AYE-AYE SNUFFLES
0:39:01 > 0:39:04This camera is so sensitive, it picks up
0:39:04 > 0:39:08on tiny changes in temperature, like the breath on my moustache.
0:39:16 > 0:39:19And it highlights something rather unexpected.
0:39:20 > 0:39:25Unlike her other fingers, Ardrey's feeding finger is stone cold.
0:39:26 > 0:39:30It has virtually no blood flow to it at all.
0:39:41 > 0:39:43But as she starts foraging,
0:39:43 > 0:39:47blood rushes to thousands of nerve endings in her fingertip,
0:39:47 > 0:39:49making it incredibly sensitive.
0:39:55 > 0:39:57And in a specially constructed log,
0:39:57 > 0:40:01we can get a look at that ET-like finger at work.
0:40:04 > 0:40:07A unique knuckle, much like our shoulder joint,
0:40:07 > 0:40:11means her finger can move in any direction.
0:40:12 > 0:40:17And it's now so sensitive that like a blind person reads brail,
0:40:17 > 0:40:20she can detect the slightest movement.
0:40:30 > 0:40:34That is one of the most remarkable tools in the whole animal kingdom
0:40:34 > 0:40:37and it allows the aye-aye to carve out a niche
0:40:37 > 0:40:42so specific that in terms of finding food, it's in a league of its own.
0:40:49 > 0:40:51The aye-aye is the ultimate specialist.
0:40:57 > 0:41:00But when it comes to finding food, the world is
0:41:00 > 0:41:01full of possibilities.
0:41:07 > 0:41:09You just need to spot an opportunity...
0:41:13 > 0:41:14..and make the most of it.
0:41:20 > 0:41:23Primate ingenuity means there are no
0:41:23 > 0:41:25bounds to their gastronomic ambition.
0:41:35 > 0:41:37For olive baboons,
0:41:37 > 0:41:42the savannahs around Lake Bogoria in Kenya are a land of plenty.
0:41:53 > 0:41:59Insect grubs hidden in flamingo dung provide a welcome protein boost.
0:42:04 > 0:42:07Some, however, are far more ambitious.
0:42:22 > 0:42:24Timing is everything.
0:42:52 > 0:42:57Once one baboon has worked it out, the whole troop soon catches on.
0:43:20 > 0:43:23Hunting live prey requires ambition...
0:43:25 > 0:43:26..speed...
0:43:28 > 0:43:29..and coordination.
0:43:49 > 0:43:53For a hungry primate, meat is the ultimate food of all.
0:44:04 > 0:44:07Primate diversity is shaped by home and diet.
0:44:10 > 0:44:12And, I think, by one more thing.
0:44:17 > 0:44:20They're social animals, they live in families,
0:44:20 > 0:44:23and as we all know, good communication skills
0:44:23 > 0:44:26are essential for a harmonious family life.
0:44:31 > 0:44:33And this need to communicate has also
0:44:33 > 0:44:36influenced how they look and behave.
0:44:43 > 0:44:47It's hard to believe that these chilled out monkeys
0:44:47 > 0:44:49are the loudest on the planet.
0:44:53 > 0:44:55But there is one way to spur them into action.
0:45:07 > 0:45:10Right, the whole monkey troop is right here in this tree.
0:45:10 > 0:45:12There's females, there's young ones,
0:45:12 > 0:45:15but the one I want you to watch is the alpha male right here.
0:45:15 > 0:45:17Watch what happens.
0:45:18 > 0:45:20HE MAKES MONKEY NOISES
0:45:28 > 0:45:31MONKEY ROARS
0:45:35 > 0:45:38ROARING CONTINUES
0:45:39 > 0:45:41That is very impressive.
0:45:41 > 0:45:45That monkey can produce 90 decibels, which is enough to...
0:45:45 > 0:45:47MONKEY ROARS
0:45:47 > 0:45:48..well, drown me out.
0:45:51 > 0:45:54MONKEY ROARS
0:46:00 > 0:46:04The howler monkey's roar is a call to arms.
0:46:04 > 0:46:06MONKEY ROARS
0:46:09 > 0:46:12A reply to my rather poor impersonation of a rival.
0:46:16 > 0:46:18MONKEY ROARS
0:46:20 > 0:46:23The male's calls soon sets off the entire troop.
0:46:23 > 0:46:26MONKEYS ROAR
0:46:27 > 0:46:30The clever thing is that by calling together,
0:46:30 > 0:46:34they make their group seem much bigger than it actually is
0:46:34 > 0:46:38and the bigger the call, the louder the noise,
0:46:38 > 0:46:40the more terrifying it is.
0:46:41 > 0:46:44The secret to the sheer volume of a howler's roar
0:46:44 > 0:46:47is in the design of its unusual throat.
0:46:48 > 0:46:50When a howler monkey calls,
0:46:50 > 0:46:53it flares out its lips like a natural loud-hailer
0:46:53 > 0:46:55and it drops its jaw.
0:46:55 > 0:47:00The throat contains an enormous hollow bone that reverberates
0:47:00 > 0:47:04like a gong, giving the voice an amazing amount of extra clout.
0:47:04 > 0:47:07MONKEYS ROAR
0:47:10 > 0:47:13All this noise sends a message to neighbouring troops -
0:47:13 > 0:47:15keep off our patch or there'll be trouble.
0:47:17 > 0:47:19MONKEYS ROAR
0:47:26 > 0:47:29The pitch of their voice is as important as the volume.
0:47:33 > 0:47:35Higher frequencies are easily scattered,
0:47:35 > 0:47:39but low roars punch through the forest for up to a mile.
0:47:42 > 0:47:44ECHOING ROARS SPREAD
0:47:49 > 0:47:53It's this mosaic of sound that sets clear-cut home ranges
0:47:53 > 0:47:55across the entire forest.
0:48:01 > 0:48:05Shouting at your neighbours may seem like a waste of energy,
0:48:05 > 0:48:06but by howling every day,
0:48:06 > 0:48:08families can avoid coming into
0:48:08 > 0:48:12contact with each other, and when they do, disagreements are easily
0:48:12 > 0:48:18settled at arm's length, and that is a great way to keep the peace.
0:48:26 > 0:48:29While a howler monkey's world is shaped by sound,
0:48:29 > 0:48:33other primates communicate in a much more visual way.
0:48:49 > 0:48:52Mandrills live in the dark and impenetrable
0:48:52 > 0:48:55forests of Gabon in West Africa.
0:48:58 > 0:49:02And here, vision plays a key role in finding a mate.
0:49:14 > 0:49:17It's thought that female mandrills spend
0:49:17 > 0:49:20most of the year in large all-girl groups.
0:49:25 > 0:49:28But in the breeding season, their peace is shattered.
0:49:40 > 0:49:43Male mandrills are a very different animal.
0:49:54 > 0:50:00These huge beasts dwarf the females, three times their size.
0:50:07 > 0:50:11They're the largest monkeys on the planet, and the most colourful.
0:50:16 > 0:50:21Those vibrant hues are a display of strength and power.
0:50:42 > 0:50:45The big brutes pitch up to fight for the girls.
0:50:59 > 0:51:04When two males catch each other's eye, it's a standoff.
0:51:04 > 0:51:07MONKEYS CHATTER
0:51:21 > 0:51:24An actual fight is a high-risk strategy -
0:51:24 > 0:51:26it could mean injury or death.
0:51:35 > 0:51:38Every single muscle twitch has a meaning.
0:51:53 > 0:51:54It's all over.
0:51:54 > 0:51:57A grimace is a sign of submission.
0:52:01 > 0:52:04The battle has been avoided.
0:52:07 > 0:52:10And the loser lives to fight another day.
0:52:15 > 0:52:18The victor is one step closer to becoming king.
0:52:21 > 0:52:22And after a bout like this,
0:52:22 > 0:52:27a surge in testosterone will make a male's colours even more vivid.
0:52:45 > 0:52:46After weeks of posturing,
0:52:46 > 0:52:50the healthiest male becomes the most colourful.
0:52:53 > 0:52:57And the object of all the females' desire.
0:53:01 > 0:53:04The single most colourful male will mate with over three
0:53:04 > 0:53:05quarters of the group.
0:53:11 > 0:53:15He'll have their undivided attention for at least a couple of months.
0:53:21 > 0:53:26Proof if ever you need it that in the mandrill mating game,
0:53:26 > 0:53:28looks really matter.
0:53:41 > 0:53:47The challenges of where we live, what we eat and
0:53:47 > 0:53:52how we live together have shaped our incredible animal family.
0:53:59 > 0:54:00But the world is changing.
0:54:07 > 0:54:10In the 21st century, the ultimate challenge
0:54:10 > 0:54:13to any monkey is living alongside the most
0:54:13 > 0:54:15successful primate of all...
0:54:17 > 0:54:18..humans.
0:54:24 > 0:54:27But even the urban jungle is a land of opportunity
0:54:27 > 0:54:30for those who are smart enough to exploit it.
0:54:48 > 0:54:53For the resident rhesus macaques, a market-side pitch like this is what
0:54:53 > 0:54:55life's all about.
0:55:09 > 0:55:13They may not be the prettiest, or look the most remarkable,
0:55:13 > 0:55:17but macaques are the most successful monkeys on the planet.
0:55:23 > 0:55:28They're adaptable, devious and they work together as a team.
0:55:36 > 0:55:40In their search for food, hungry macaques have swapped jungle vines
0:55:40 > 0:55:42for power lines.
0:55:55 > 0:55:58Gangs leave a trail of destruction in their wake.
0:56:10 > 0:56:13They're smart enough to spot the tiniest of opportunities.
0:56:30 > 0:56:33First up, the brave ones scope out the joint.
0:56:43 > 0:56:46Lookouts are posted to watch for trouble...
0:56:47 > 0:56:50and once the coast is clear, it's a free-for-all.
0:57:02 > 0:57:04These opportunistic criminals
0:57:04 > 0:57:06ransack a house in a matter of minutes.
0:57:14 > 0:57:16And at the slightest hint of trouble...
0:57:18 > 0:57:19..they make their escape.
0:57:31 > 0:57:35Thanks to their agile bodies, and adaptable minds,
0:57:35 > 0:57:38macaques can beat us humans at our own game.
0:57:44 > 0:57:45To these incredible monkeys,
0:57:45 > 0:57:48the urban jungle is just one big playground.
0:57:54 > 0:57:56We primates are truly remarkable.
0:57:56 > 0:57:58Not only are we physically adaptable,
0:57:58 > 0:58:02we're also smart and can work as a team.
0:58:02 > 0:58:06And that's a winning combination that allows us to survive,
0:58:06 > 0:58:09even thrive in an ever-changing world.
0:58:13 > 0:58:15Join me next time when we delve
0:58:15 > 0:58:18into the sociable world of the primate family.
0:58:23 > 0:58:25And it's not as harmonious as you might think.
0:58:27 > 0:58:29You need to make friends.
0:58:31 > 0:58:33Avoid your enemies.
0:58:33 > 0:58:35Look at that!
0:58:35 > 0:58:37And find your place on the social ladder.