0:00:03 > 0:00:05The natural world is full of extraordinary animals
0:00:05 > 0:00:07with amazing life histories.
0:00:09 > 0:00:12Yet certain stories are more intriguing than most.
0:00:15 > 0:00:18The mysteries of a butterfly's life cycle
0:00:18 > 0:00:21or the strange biology of the emperor penguin.
0:00:21 > 0:00:24Some of these creatures were surrounded
0:00:24 > 0:00:28by myth and misunderstandings for a very long time.
0:00:29 > 0:00:33And some have only recently revealed their secrets.
0:00:34 > 0:00:38These are the animals that stand out from the crowd,
0:00:38 > 0:00:42the curiosities I find particularly fascinating.
0:00:50 > 0:00:55Orang-utans have an extraordinary ability to use tools
0:00:55 > 0:00:59but the full extent of their skills remained undiscovered for centuries.
0:01:00 > 0:01:04Surprisingly, crows also make tools.
0:01:07 > 0:01:12How and why have these two very different animals become so inventive?
0:01:26 > 0:01:31When I first saw orang-utans that had been raised in captivity using tools,
0:01:31 > 0:01:34I was truly astonished.
0:01:34 > 0:01:39They were extraordinarily skilful at imitating the things we do.
0:01:42 > 0:01:46But at the time, such skills had never been observed
0:01:46 > 0:01:49among wild orang-utans.
0:01:51 > 0:01:54So, are these apes just clever mimics
0:01:54 > 0:01:57or do they ever make and use tools in the wild?
0:01:58 > 0:02:03We didn't know the answers to such questions until quite recently.
0:02:05 > 0:02:10This dramatic sculpture by the French artist Emmanuel Fremiet,
0:02:10 > 0:02:14entitled An Orang-utan Strangling A Borneo Native,
0:02:14 > 0:02:19represents the image people had of this formidable giant ape.
0:02:19 > 0:02:22It's pretty accurate, as Fremiet studied live orangs
0:02:22 > 0:02:24at the Jardin des Plantes in Paris
0:02:24 > 0:02:27and you can see why orangs are so called.
0:02:27 > 0:02:32The name in Malay means "orang" - people - and "utan" - of the forest.
0:02:34 > 0:02:38At first, orang-utans were feared and misunderstood.
0:02:39 > 0:02:41Early explorers thought
0:02:41 > 0:02:45that these long-armed, tree-living apes were degenerate human beings
0:02:45 > 0:02:49and for centuries their true nature and behaviour in the wild
0:02:49 > 0:02:51was largely unknown.
0:02:54 > 0:02:58Orang-utans are only found in the rainforests of Indonesia -
0:02:58 > 0:03:02one population in Borneo and another, slightly different one,
0:03:02 > 0:03:05in the island of Sumatra to the west.
0:03:07 > 0:03:12They have strong, dexterous hands and feet and a very mobile mouth
0:03:12 > 0:03:16that enable them to break open and eat the fruits on which they depend.
0:03:16 > 0:03:19But although they're clearly very intelligent,
0:03:19 > 0:03:22the only tools they seemed to use were sticks,
0:03:22 > 0:03:25which they wielded in a very simple way.
0:03:27 > 0:03:31Yet in Africa, chimpanzees had been seen using tools
0:03:31 > 0:03:33in a rather more complex fashion.
0:03:36 > 0:03:42Back in 1871, Darwin had reported wild chimpanzees cracking open
0:03:42 > 0:03:44walnut-like fruits with stones.
0:03:45 > 0:03:49And in the 1960s they were even seen modifying sticks
0:03:49 > 0:03:52with which they fished for termites.
0:03:54 > 0:03:59It seemed strange that while wild chimps used tools in a quite complicated way,
0:03:59 > 0:04:02orang-utans, apparently, did not.
0:04:05 > 0:04:09Orangs, unlike chimps, are not very sociable.
0:04:09 > 0:04:12Individuals are largely solitary.
0:04:13 > 0:04:16The males have large individual territories
0:04:16 > 0:04:20within which several females have their own home ranges.
0:04:23 > 0:04:26This more solitary way of life affects
0:04:26 > 0:04:30the way orangs share their knowledge and develop their skills.
0:04:32 > 0:04:35The most social time of an orang-utan's life
0:04:35 > 0:04:36is when it's a baby,
0:04:36 > 0:04:39and in the wild, youngsters stay with their mothers
0:04:39 > 0:04:42for the first six years of their lives.
0:04:42 > 0:04:44During this time, they learn the skills
0:04:44 > 0:04:47needed to survive in the forest alone.
0:04:47 > 0:04:50They need to know how to climb, build nests
0:04:50 > 0:04:54and how to solve problems such as breaking into tough food,
0:04:54 > 0:04:58and their large brains certainly help them to master these tasks.
0:05:02 > 0:05:05So, a young orang behaves like its mother
0:05:05 > 0:05:08and copies the way she searches for food and prepares it to eat.
0:05:11 > 0:05:14In captivity, they readily make tools
0:05:14 > 0:05:17to reach food or to escape from their enclosures.
0:05:17 > 0:05:20They're clearly very inventive
0:05:20 > 0:05:23and good at developing ways to solve particular problems.
0:05:24 > 0:05:29So, it was a puzzle as to why such bright and capable apes
0:05:29 > 0:05:32were apparently not behaving in a similar way in the wild.
0:05:36 > 0:05:39Orangs are clever and physically dexterous.
0:05:39 > 0:05:42They have very strong jaws and mobile hands and feet
0:05:42 > 0:05:47and in the wild they can reach and prise open most food.
0:05:47 > 0:05:49It was assumed for many years
0:05:49 > 0:05:51that even though they used tools in captivity,
0:05:51 > 0:05:54they didn't perhaps need to do so in the wild.
0:05:55 > 0:06:00It seems that, strangely, these great apes have more skills
0:06:00 > 0:06:03than they normally need for their lives in the wild.
0:06:05 > 0:06:10It wasn't until 1964 that orangs were studied in detail.
0:06:10 > 0:06:13A Lithuanian scientist from Canada
0:06:13 > 0:06:16called Birute Galdikas settled in Borneo
0:06:16 > 0:06:19to live alongside these great apes.
0:06:19 > 0:06:23For over 30 years, she watched both tame orangs
0:06:23 > 0:06:26and wholly wild ones in the forests.
0:06:26 > 0:06:30In her camp, she found that the tame ones quickly discovered
0:06:30 > 0:06:34how to use tools in a relatively sophisticated way.
0:06:35 > 0:06:38But in the wild, she only saw them build nests
0:06:38 > 0:06:41and use sticks in a simple fashion.
0:06:43 > 0:06:47That picture of the character and abilities of orangs
0:06:47 > 0:06:50remained unchanged for a long time.
0:06:52 > 0:06:57Then, in 1994, our understanding of orangs changed radically.
0:06:58 > 0:07:03A group of Swiss scientists observed some orangs
0:07:03 > 0:07:05that were behaving very differently.
0:07:07 > 0:07:10They lived several hundred miles away from their Borneo cousins
0:07:10 > 0:07:14in swampy rainforests on the island of Sumatra.
0:07:18 > 0:07:21The orang's diet is about 90% fruit,
0:07:21 > 0:07:23and this is one of their favourites.
0:07:23 > 0:07:26It's a durian and it's well known -
0:07:26 > 0:07:28ugh! - for its pungent smell.
0:07:28 > 0:07:32As you can see, it's got a very spiky case,
0:07:32 > 0:07:34but orangs are able to break it open
0:07:34 > 0:07:37and reach the soft, pulpy flesh inside.
0:07:38 > 0:07:43But it's when they tackle another similar spiky fruit, called neesia,
0:07:43 > 0:07:45which is more difficult to open,
0:07:45 > 0:07:49that scientists got their first glimpse of orangs making tools.
0:07:49 > 0:07:52Neesia presents an extra challenge
0:07:52 > 0:07:55because inside it contains rich, nutritious seeds
0:07:55 > 0:08:00which are embedded in a mass of sharp, needle-like hairs.
0:08:02 > 0:08:05To avoid touching these irritating hairs,
0:08:05 > 0:08:10the swamp-living orangs slid sticks into cracks in the fruit husks.
0:08:10 > 0:08:12Then they pushed them up and down
0:08:12 > 0:08:14to flick out the hairs and free the seeds.
0:08:16 > 0:08:17They also modified sticks
0:08:17 > 0:08:21so that they fitted different-sized cracks in the fruits.
0:08:24 > 0:08:27The particular fruit that grew in these wet forests
0:08:27 > 0:08:32had stimulated the Sumatran orangs to make and use special tools.
0:08:35 > 0:08:38Unusually for such solitary creatures,
0:08:38 > 0:08:41they gathered at these rich feeding areas in a group
0:08:41 > 0:08:45and, feeding close to one another, they shared their skills.
0:08:46 > 0:08:50So now it was realised that orangs were not just mimics.
0:08:50 > 0:08:54They were able to invent their own ways of making and using tools,
0:08:54 > 0:08:56just like chimps.
0:09:02 > 0:09:06We have long known that captive orangs can quickly work out
0:09:06 > 0:09:07ways to solve problems
0:09:07 > 0:09:12and now it was clear that wild orangs are no different.
0:09:15 > 0:09:20In recent years, they've been seen using sticks to fish for termites and honey
0:09:20 > 0:09:23in much the same way as individuals do in captivity.
0:09:27 > 0:09:28In the flooded forests,
0:09:28 > 0:09:32many insects are forced above ground to live in tree holes,
0:09:32 > 0:09:35so the orangs use sticks to extract them.
0:09:36 > 0:09:38It seems incredible
0:09:38 > 0:09:43that tool use in wild orangs took hundreds of years to discover.
0:09:44 > 0:09:47In fact, it had been happening all the time,
0:09:47 > 0:09:49just hidden away from view.
0:09:50 > 0:09:55These red men and women of the forest have
0:09:55 > 0:09:57very dexterous hands and feet,
0:09:57 > 0:10:00strong jaws and a large brain.
0:10:00 > 0:10:04In the wild they have little need for complex tools,
0:10:04 > 0:10:09and being solitary means that tool use is not usually shared or spread.
0:10:10 > 0:10:13But even as loners, they are inventive
0:10:13 > 0:10:15and can work out how to solve problems.
0:10:15 > 0:10:20Here is a creature that could be one of the greatest tool users
0:10:20 > 0:10:22in the animal kingdom.
0:10:23 > 0:10:28Orang-utan tool use was not discovered for many years.
0:10:29 > 0:10:33Next, meet the clever crow, that also makes tools.
0:10:34 > 0:10:39How have crows' curious minds helped them become so inventive?
0:10:39 > 0:10:42SQUAWKING
0:10:47 > 0:10:51The most famous members of the crow family in Britain
0:10:51 > 0:10:55are the ravens that live here in the Tower of London.
0:10:55 > 0:10:58By tradition, they protect the Crown
0:10:58 > 0:11:03and they are recruited and indeed dismissed from the British Army,
0:11:03 > 0:11:04just like soldiers.
0:11:05 > 0:11:10In 1986, one of them, called George, had to be exiled to Wales
0:11:10 > 0:11:12for persistent bad behaviour
0:11:12 > 0:11:15in destroying the television aerials around here.
0:11:15 > 0:11:18And more recently, another one,
0:11:18 > 0:11:20noticing that one of its fellows had died
0:11:20 > 0:11:23and was attracting a great deal of attention,
0:11:23 > 0:11:25also lay down on the ground, feigning death,
0:11:25 > 0:11:28and when the Raven Master came over to see what the matter was,
0:11:28 > 0:11:30he got a sharp peck.
0:11:31 > 0:11:33Well, stories like those suggest
0:11:33 > 0:11:36that members of the crow family have minds
0:11:36 > 0:11:39rather different from other birds.
0:11:43 > 0:11:47Ravens are cheeky, self-aware and socially intelligent.
0:11:51 > 0:11:54They're part of the big crow family
0:11:54 > 0:11:56that in Britain includes hooded and carrion crows,
0:11:56 > 0:12:00jackdaws, jays, choughs and magpies.
0:12:04 > 0:12:07Their brains are twice as large as other birds',
0:12:07 > 0:12:10and, relative to body size, comparable to a chimpanzee's.
0:12:13 > 0:12:16This extra brain capacity has helped them
0:12:16 > 0:12:19become very good at solving problems.
0:12:26 > 0:12:28Here is Bran the raven
0:12:28 > 0:12:32and I've put a screen in front of his cage
0:12:32 > 0:12:34so he can't see what's going on.
0:12:34 > 0:12:37And this is Bran's stone.
0:12:37 > 0:12:40He's had it since he was a chick
0:12:40 > 0:12:46and he can recognise it amongst a whole pile of other pebbles.
0:12:46 > 0:12:50Now, I've put a few of a similar size on this grid
0:12:50 > 0:12:53and I'll put his stone just there.
0:12:53 > 0:12:56And now we'll see whether he can find it.
0:12:59 > 0:13:02Bran, where's your stone?
0:13:07 > 0:13:09Immediately! Well done!
0:13:11 > 0:13:12The only explanation of this
0:13:12 > 0:13:17is that he has an extremely acute visual memory.
0:13:17 > 0:13:18Indeed he has.
0:13:23 > 0:13:27You could say that by putting stones on a gridded square like that
0:13:27 > 0:13:30makes each one very obvious.
0:13:30 > 0:13:33All right, well, let's make things a little more difficult.
0:13:33 > 0:13:38This is his stone and I'll put it in this pile of stones
0:13:38 > 0:13:41so that he can only see just a little tip of it.
0:13:43 > 0:13:46Now, Bran, where's your stone?
0:13:48 > 0:13:50Oh, come on!
0:13:50 > 0:13:51HE CHUCKLES
0:13:53 > 0:13:56Fantastic! Thank you very much.
0:13:58 > 0:14:03And this ability to recognise a little, small detail
0:14:03 > 0:14:06is used by these birds when they cache food.
0:14:06 > 0:14:11In the good times, they will hide hundreds of different pieces of food
0:14:11 > 0:14:14and conceal them and remember every one
0:14:14 > 0:14:19and come back to it in the hard times to pick up that piece of food.
0:14:19 > 0:14:23Extraordinary. You're an amazing bird, Bran.
0:14:24 > 0:14:27Another species of crow, Clarke's nutcracker,
0:14:27 > 0:14:30is a champion at caching food.
0:14:30 > 0:14:35It collects and hides up to 33,000 seeds every season
0:14:35 > 0:14:40and remembers where each one is put for up to nine months.
0:14:41 > 0:14:44It can even find them under snow.
0:14:46 > 0:14:50Crows also remember the kind of food that they have hidden.
0:14:50 > 0:14:53Freshly buried grubs perish quickly,
0:14:53 > 0:14:56so need to be recovered sooner than seeds.
0:14:57 > 0:15:01The ability to think ahead and anticipate future events
0:15:01 > 0:15:04can also help in other situations.
0:15:05 > 0:15:08Other birds will steal buried food, if they can find it.
0:15:08 > 0:15:12But some kinds of crows are able to recognise these thieves
0:15:12 > 0:15:13and outwit them.
0:15:13 > 0:15:15SQUAWKING
0:15:15 > 0:15:18Recent research at Cambridge has revealed
0:15:18 > 0:15:22that scrub jays take great care in how they hide their food.
0:15:24 > 0:15:28One jay is given the choice of two locations in which to cache food -
0:15:28 > 0:15:32under stones, which make a noise if they are moved,
0:15:32 > 0:15:35or soil, which can be cleared away quietly.
0:15:36 > 0:15:40In the cage next door, another scrub jay watches.
0:15:40 > 0:15:42He's a potential thief.
0:15:45 > 0:15:48When the caching jay knows that its neighbour can see,
0:15:48 > 0:15:51it buries its food under stones.
0:15:53 > 0:15:57If the jay next door attempts to steal that buried food,
0:15:57 > 0:16:00the noisy stones will act like a burglar alarm.
0:16:02 > 0:16:04But when a screen is added
0:16:04 > 0:16:07so that the neighbouring jay can only hear what's happening,
0:16:07 > 0:16:10the caching jay changes its plan.
0:16:10 > 0:16:13This time, it decides to bury its food under soil,
0:16:13 > 0:16:15which makes hardly any noise,
0:16:15 > 0:16:18so its location remains unknown to the jay next door.
0:16:21 > 0:16:23CAWING
0:16:25 > 0:16:27For centuries, members of the crow family
0:16:27 > 0:16:30have been recognised to be unusual birds.
0:16:32 > 0:16:35Their noisy gatherings gave them a sinister reputation
0:16:35 > 0:16:38but their intelligence was legendary.
0:16:42 > 0:16:44In one of Aesop's fables,
0:16:44 > 0:16:47a clever crow drops pebbles into a jug of water
0:16:47 > 0:16:50to raise the level high enough so that it can drink.
0:16:50 > 0:16:53This is perhaps one of the first recorded examples
0:16:53 > 0:16:55of a crow using a tool.
0:16:57 > 0:17:01Here, once again, is Bran the raven
0:17:01 > 0:17:04and, like the crow in Aesop's fable,
0:17:04 > 0:17:08he's extremely intelligent and clever at collecting food.
0:17:08 > 0:17:11I'm going to set him a problem which he has seen before
0:17:11 > 0:17:14and for which he produced his own solution.
0:17:14 > 0:17:18I'm going to take a little bit of meat,
0:17:18 > 0:17:20put it in this plastic bottle
0:17:20 > 0:17:23and then, just to make it difficult for him,
0:17:23 > 0:17:27I'm going to crush the bottle...
0:17:29 > 0:17:31..so that it won't come out just by shaking it.
0:17:32 > 0:17:36Now, then, Bran, how are you going to get that out?
0:17:47 > 0:17:50HE LAUGHS
0:17:52 > 0:17:56What he did was to take this bottle, put it in the water
0:17:56 > 0:17:59and use the water to swill it out and collect the bit
0:17:59 > 0:18:02and he did that in about ten seconds flat!
0:18:07 > 0:18:10Bran, in effect, used the water as a tool.
0:18:11 > 0:18:15And he's very quick to understand the potential of any object
0:18:15 > 0:18:19and work out how it might help solve one of his problems.
0:18:22 > 0:18:26All crows, it seems, have extraordinary memories,
0:18:26 > 0:18:30acute vision and great ingenuity in devising tools.
0:18:34 > 0:18:38In New Caledonia, a tropical island east of Australia,
0:18:38 > 0:18:43wild crows use tools just as expertly and inventively as apes.
0:18:46 > 0:18:49They fashion sticks to tease grubs out
0:18:49 > 0:18:52from places they would otherwise find impossible to reach.
0:18:57 > 0:19:01More recently, scientists discovered and filmed crows
0:19:01 > 0:19:04that had taken their tool-making a stage further.
0:19:05 > 0:19:07They were creating hooks
0:19:07 > 0:19:10by carefully modifying the thick ends of twigs.
0:19:13 > 0:19:15This seemed extraordinary,
0:19:15 > 0:19:18but there were more surprises.
0:19:19 > 0:19:22On the nearby island of Grande Terre,
0:19:22 > 0:19:26the crows were making even more sophisticated implements.
0:19:29 > 0:19:33These are the actual tools made by New Caledonian crows.
0:19:33 > 0:19:36They're constructed from the leaves of the pandanus tree,
0:19:36 > 0:19:40which have lines of sharp spikes along their margins
0:19:40 > 0:19:45and the crows use them to winkle insects out of crevices.
0:19:45 > 0:19:50But each population of these crows makes the tool in their own way.
0:19:50 > 0:19:54This one is a broad strip.
0:19:55 > 0:19:58This one, a very thin strip.
0:19:59 > 0:20:03And these two, which come from the north of the island,
0:20:03 > 0:20:05are used by two different populations.
0:20:05 > 0:20:10One makes a two-step tool, thin at the end,
0:20:10 > 0:20:14and this one makes a one-, two-, three-step tool.
0:20:16 > 0:20:18In this rare footage,
0:20:18 > 0:20:22the crow strips off the serrated edge of a leaf.
0:20:24 > 0:20:28The series of small spines are better than just a single hook
0:20:28 > 0:20:32because they can snag an insect along all its length.
0:20:37 > 0:20:42Each population of the crows have their own design
0:20:42 > 0:20:45which they pass on to the next generation.
0:20:45 > 0:20:47So, just like us,
0:20:47 > 0:20:50these New Caledonian crows have their own cultures,
0:20:50 > 0:20:54their own inquisitive, curious minds,
0:20:54 > 0:20:58which is pretty unusual for a bird.
0:20:59 > 0:21:03Orang-utans in the wild make very simple tools.
0:21:03 > 0:21:06But surprisingly, it's the smart crows that take the prize
0:21:06 > 0:21:11for making the most sophisticated tools used by any animal.
0:21:11 > 0:21:12Very clever.
0:21:14 > 0:21:15Are we finished now?
0:21:16 > 0:21:18Where's my lunch?