0:00:06 > 0:00:09Millions of us love watching the world's wildlife
0:00:09 > 0:00:12behaving in strange and wonderful ways.
0:00:18 > 0:00:22But what lies at the heart of these extraordinary behaviours?
0:00:25 > 0:00:28Can science explain what's really going on?
0:00:31 > 0:00:34The latest research from all around the world is increasing
0:00:34 > 0:00:38our understanding of animal emotions, relationships,
0:00:38 > 0:00:42intelligence and communication faster than ever before.
0:00:42 > 0:00:44ROARING
0:00:46 > 0:00:48I'm Hugh Fearnley-Whittingstall
0:00:48 > 0:00:51and I've teamed up with wildlife experts to travel the globe
0:00:51 > 0:00:54in search of the most surprising animal stories.
0:00:55 > 0:00:59- Ooh, there, there, there, there! - Wow! Look at him!
0:00:59 > 0:01:01Using the very latest camera technology,
0:01:01 > 0:01:06we'll reveal how and why animals do such remarkable things.
0:01:08 > 0:01:09And we'll meet the scientists...
0:01:09 > 0:01:11Let's go through here.
0:01:11 > 0:01:13..who dedicate their lives to understanding
0:01:13 > 0:01:15these extraordinary discoveries.
0:01:26 > 0:01:31Tonight, we explore the amazing anatomies of some remarkable animals
0:01:31 > 0:01:34and the new research that's helping us to understand how
0:01:34 > 0:01:38they're perfectly adapted to live in some of the world's
0:01:38 > 0:01:39most challenging environments.
0:01:42 > 0:01:45Zoologist Lucy Cooke is in Costa Rica to find out
0:01:45 > 0:01:49if the sloth's famed laziness could be the key to its success.
0:01:51 > 0:01:55Conservationist Giles Clark is in Australia meeting a kangaroo
0:01:55 > 0:01:59that's happier climbing trees than hopping through the Outback.
0:01:59 > 0:02:04Biologist Patrick Aryee discovers how a fox with super-sensitive
0:02:04 > 0:02:08hearing can thrive in one of the harshest habitats on earth.
0:02:09 > 0:02:11And marine biologist Shanta Barley
0:02:11 > 0:02:15reveals the secrets of the world's oddest-looking creature.
0:02:17 > 0:02:20But, first, I'm going to find out how one man's incredible
0:02:20 > 0:02:23understanding of an eagle's physical abilities
0:02:23 > 0:02:28could unlock its potential and help save a species from extinction.
0:02:31 > 0:02:34With a wingspan of almost 2.5 metres,
0:02:34 > 0:02:38the white-tailed eagle is the largest eagle in Europe.
0:02:38 > 0:02:42These supreme masters of the sky have
0:02:42 > 0:02:45a sophisticated, high-performance anatomy.
0:02:45 > 0:02:47Wings built to soar.
0:02:47 > 0:02:51Sharp eyes to spot prey with pinpoint accuracy.
0:02:52 > 0:02:56And talons to snatch and grab with power and precision.
0:02:58 > 0:03:01Scientists have long thought it would be impossible to teach
0:03:01 > 0:03:05a captive-bred eagle to fly and hunt like a wild one.
0:03:07 > 0:03:10But professional falconer Jacques Olivier Travers
0:03:10 > 0:03:12is defying conventional wisdom.
0:03:12 > 0:03:16He believes he can train eagles born in captivity
0:03:16 > 0:03:19to harness the full potential of their anatomy
0:03:19 > 0:03:22and master the vital survival skills
0:03:22 > 0:03:24for a successful return to the wild.
0:03:25 > 0:03:29I'm meeting Jacques Olivier at his aviary in the French Alps,
0:03:29 > 0:03:32where he's about to introduce me to his top student.
0:03:34 > 0:03:38- This is Victor.- Wow! He's very happy to see you.- Oh, yeah, yeah, yeah.
0:03:40 > 0:03:42- Whoa! Off he goes!- Yeah, no problem.
0:03:42 > 0:03:46'Seven-year-old Victor is part of a captive-breeding programme
0:03:46 > 0:03:51'and has already been trained to make short flights to a food reward.'
0:03:51 > 0:03:53Ooh-hoo! Extraordinary.
0:03:53 > 0:03:57I just felt the wing beats going across my head there. Such power.
0:03:57 > 0:04:00Yeah, it's a very powerful bird.
0:04:00 > 0:04:03You've got quite a few different types of eagle here,
0:04:03 > 0:04:05but I know the white-tailed's really special.
0:04:05 > 0:04:07Why is this such a special bird for you?
0:04:07 > 0:04:09I discovered this bird in a book.
0:04:09 > 0:04:12I said, "Wow! I've never seen this bird. I want to see one."
0:04:12 > 0:04:15And I had to wait for a long time, more than 20 years,
0:04:15 > 0:04:16to see my first one.
0:04:16 > 0:04:18But when I discovered this bird,
0:04:18 > 0:04:20I fell in love with him and I thought,
0:04:20 > 0:04:22"I have to do something for this bird because it disappears
0:04:22 > 0:04:25"because of us, because we kill all of them."
0:04:26 > 0:04:29In the wild, they're skilled at using their magnificent
0:04:29 > 0:04:31biology to hunt prey.
0:04:33 > 0:04:36But, historically, the hunters became the hunted.
0:04:36 > 0:04:40Seen as a threat to livestock in Britain and in France,
0:04:40 > 0:04:42the white-tailed eagle was wiped out in both countries
0:04:42 > 0:04:45by the early 20th century.
0:04:47 > 0:04:51Now the only white-tailed eagles in France are in aviaries or zoos.
0:04:55 > 0:04:57Here he comes!
0:04:57 > 0:05:01Ooh-hoo! That's amazing!
0:05:03 > 0:05:08'To fly in the wild, Victor must be able to glide and soar in the wind.
0:05:08 > 0:05:12'That's lesson one of Jacques Olivier's basic training.
0:05:18 > 0:05:21'And it's based on the principle that for a man to teach an eagle
0:05:21 > 0:05:26'to fly, he has to think like an eagle and fly like one, too.'
0:05:30 > 0:05:31A bird who is born in captivity
0:05:31 > 0:05:34knows how to go from Point A to Point B.
0:05:34 > 0:05:37But to use the pheromone, to use the wind, to use the mountains,
0:05:37 > 0:05:39everything, the parents teach him.
0:05:39 > 0:05:43And the paraglider is the best thing for that.
0:05:43 > 0:05:46- Do you feel like a bird yourself? More bird than human?- Yeah. Exactly.
0:05:46 > 0:05:50And what is amazing, it's for three, four weeks,
0:05:50 > 0:05:53when you start to fly, I'm better than him.
0:05:53 > 0:05:58But, after one month, they fly so well that I can't follow them.
0:06:00 > 0:06:03A tiny camera in a harness on the eagle's back gives
0:06:03 > 0:06:07Jacques Olivier an amazing insight into his rookie's flight.
0:06:07 > 0:06:10Well, the first time you're on the back of a bird,
0:06:10 > 0:06:13you can feel what he feels. You can see what he...
0:06:13 > 0:06:16Almost like you're riding on the back of an eagle. It's incredible.
0:06:16 > 0:06:18Yeah.
0:06:18 > 0:06:20Once an eagle has mastered the art of basic flight,
0:06:20 > 0:06:23lesson two is learning how to hunt.
0:06:24 > 0:06:27Tell me what makes him such an effective hunter.
0:06:27 > 0:06:30Yeah. You can see it's a large bird. He has amazing sight.
0:06:30 > 0:06:34He can see his prey more than 2km away.
0:06:34 > 0:06:37He has such big and powerful talons that
0:06:37 > 0:06:41- he can kill fish or rabbits, ducks, geese.- Geese?
0:06:41 > 0:06:43- He could take on a goose? - Yeah, of course.
0:06:43 > 0:06:46He has been created for hunting.
0:06:47 > 0:06:50If Jacques Olivier can teach a captive eagle
0:06:50 > 0:06:53to use its extraordinary anatomy to hunt successfully,
0:06:53 > 0:06:56then maybe it could be returned to the wild.
0:06:56 > 0:06:59But for a man to teach an eagle to hunt
0:06:59 > 0:07:02is even harder than teaching him to fly.
0:07:02 > 0:07:05The babies will see their parents catch a fish and they will,
0:07:05 > 0:07:08just because they see it, try to do the same thing.
0:07:08 > 0:07:10- So, it's imitation behaviour...? - Imitation behaviour.
0:07:10 > 0:07:13- They learn to do what their parents are doing visually.- Exactly.
0:07:13 > 0:07:17You, presumably, have not swooped down like a bird and grabbed a fish
0:07:17 > 0:07:18- off the water?- You're right.
0:07:18 > 0:07:22- You've had to do it in a different way, little by little?- Yeah.
0:07:22 > 0:07:26Small pool, bigger pool, lake and small piece of fish,
0:07:26 > 0:07:29real fish, live fish. It's different steps.
0:07:30 > 0:07:33Victor's not quite ready yet to hunt live fish in a big lake,
0:07:33 > 0:07:36but Jacques Olivier is going to show me his progress
0:07:36 > 0:07:38using bait thrown in the water.
0:07:42 > 0:07:44He got that all right.
0:07:44 > 0:07:47'It might not look much, but in slow-motion,
0:07:47 > 0:07:50'we can see the level of precision Victor has learnt.'
0:07:50 > 0:07:52Oh, beautiful!
0:07:52 > 0:07:54That was great. He really picked it up with his talons
0:07:54 > 0:07:56as though it was a fish.
0:07:57 > 0:07:59It's a sophisticated movement.
0:07:59 > 0:08:04He has to control his wing movement, his leg movement,
0:08:04 > 0:08:07the talon movement in the same second. It's very quick.
0:08:07 > 0:08:09So, Victor can catch fish for himself now?
0:08:09 > 0:08:12He can catch fish, live fish, in a training pool,
0:08:12 > 0:08:17but the last step will be live fish in a big lake.
0:08:17 > 0:08:18Because when he knows to do that,
0:08:18 > 0:08:21he don't need me and he will come back to the wild.
0:08:22 > 0:08:25But even if Victor can master the art of hunting,
0:08:25 > 0:08:30he still has to pass lesson three to ensure he can survive in the wild.
0:08:30 > 0:08:33He has to learn advanced flight,
0:08:33 > 0:08:38in the toughest part of an eagle's natural habitat - the mountains.
0:08:39 > 0:08:44Up here, Victor must be able to cope with treacherous strong winds
0:08:44 > 0:08:46and other extreme weather conditions.
0:08:49 > 0:08:53We'll join him again later when he takes on the ultimate flying test.
0:08:56 > 0:08:58BIRDSONG
0:09:00 > 0:09:024,000 miles away,
0:09:02 > 0:09:06Giles Clark's in Kenya on the trail of the hippopotamus.
0:09:07 > 0:09:10Here, a research project is revealing why one of the planet's
0:09:10 > 0:09:15largest vegetarians is the vital life-force of many African rivers.
0:09:22 > 0:09:27If ever there was an animal with an image problem, it's these guys.
0:09:27 > 0:09:29Weighing the same as your family car,
0:09:29 > 0:09:32but with the attitude of a 32-tonne truck,
0:09:32 > 0:09:36the hippopotamus is said to be the most dangerous animal in Africa.
0:09:38 > 0:09:41But that hasn't stopped ecologist Dr Doug McCauley
0:09:41 > 0:09:43from studying them for the last five years.
0:09:46 > 0:09:51- Wow!- Yeah. This pod, Giles, is probably about 25 animals.
0:09:53 > 0:09:54It's only because of Doug's expertise
0:09:54 > 0:09:57that we can get this close to the hippos.
0:09:57 > 0:09:59LOW GRUNTING
0:10:06 > 0:10:10There they go, Giles. That's your welcome here, to the hippo pods.
0:10:13 > 0:10:17- Such an incredible noise!- Yeah, I know.- So, what does that mean?
0:10:18 > 0:10:20It's definitely communication, right?
0:10:20 > 0:10:22So they're telling each other that I'm here.
0:10:22 > 0:10:27They're also communicating about threat. So, right now, you and I.
0:10:27 > 0:10:30- They're a little worried...- They've got nothing to worry about with us.
0:10:30 > 0:10:32Well, not me, anyway.
0:10:32 > 0:10:35Well, they're letting each other know that there's something strange
0:10:35 > 0:10:36here, on the river bank.
0:10:39 > 0:10:42There's a hippo over here doing a yawn display.
0:10:42 > 0:10:45But those yawns are not about waking up.
0:10:46 > 0:10:49The yawn is designed to show everyone who's boss
0:10:49 > 0:10:51by displaying their ivory tusks.
0:10:53 > 0:10:56The hippos only use their tusks in fights.
0:10:56 > 0:10:58But they are no use for eating.
0:10:58 > 0:11:01That job falls to their 60cm-wide lips
0:11:01 > 0:11:04and the huge molars at the back of their mouths.
0:11:06 > 0:11:10The hippos spend all day here, seemingly doing nothing.
0:11:10 > 0:11:12But Doug's incredible research
0:11:12 > 0:11:15has shown that this is far from the case.
0:11:15 > 0:11:16While the hippos wallow,
0:11:16 > 0:11:20they are playing a role that's supporting the whole ecosystem.
0:11:20 > 0:11:23To find out how, we're joining Doug on a mission
0:11:23 > 0:11:26to see the unique way that hippos eat.
0:11:27 > 0:11:32To feed, hippos split up from the group and travel down the river.
0:11:32 > 0:11:34When they find a suitable spot,
0:11:34 > 0:11:38they will leave the water to get to their favourite food - grass.
0:11:39 > 0:11:42And to avoid the harsh African sun,
0:11:42 > 0:11:45they prefer to graze under the cover of darkness.
0:11:45 > 0:11:48As night falls, we get into position.
0:11:48 > 0:11:50Our plan is to monitor the hippos
0:11:50 > 0:11:54with a newly-designed thermal camera that can film in the dark
0:11:54 > 0:11:58in a way that Doug's never been able to see before.
0:11:58 > 0:12:02It detects the heat from mammals' bodies up to six miles away.
0:12:02 > 0:12:04This tool is amazing.
0:12:05 > 0:12:08One of the reasons why there's just so little known about the hippo
0:12:08 > 0:12:10is because it's so hard to see them at night.
0:12:10 > 0:12:13You wouldn't want to be traipsing around
0:12:13 > 0:12:16- in that scrubby vegetation at night looking for them.- No.
0:12:17 > 0:12:21- Whoa-whoa! There, there, there, there! OK?- Wow, look at him!
0:12:21 > 0:12:23We spot three hippos.
0:12:23 > 0:12:28- Look at the light.- Yeah. So it almost looks like she's blotchy.
0:12:28 > 0:12:32Yeah. It sort of looks like camouflage, almost, doesn't it?
0:12:32 > 0:12:35First time I've seen this in a thermal camera.
0:12:35 > 0:12:38It could be that you get scarring on the hippos
0:12:38 > 0:12:40- because all these tusk marks. - When they fight.
0:12:40 > 0:12:42And so the scars are really heating up
0:12:42 > 0:12:46because there's so much more circulation going into those wounds.
0:12:46 > 0:12:48That's the only thing I can think of.
0:12:48 > 0:12:50Rather than heading into the bush to graze...
0:12:52 > 0:12:53..something spooks them
0:12:53 > 0:12:56and they disappear back to the safety of the water.
0:12:58 > 0:13:02Hippos aren't the only ones having a midnight feast.
0:13:03 > 0:13:06- So, hang on a minute, I think we have a hippo here...- Yeah, OK.
0:13:06 > 0:13:08Oh, wow, look!
0:13:09 > 0:13:12An hour later, we get what we're after.
0:13:12 > 0:13:16Hidden in the trees, the camera picks up some hippos feeding.
0:13:17 > 0:13:19This is what they're really good at.
0:13:19 > 0:13:23Their extremely wide mouths means they graze in a way
0:13:23 > 0:13:26that is very different from other herbivores.
0:13:27 > 0:13:30It's nothing at all to do with the teeth, it's all lips.
0:13:30 > 0:13:35They're using those big, horny lips to grab grass there, rip it...
0:13:35 > 0:13:36You see its head goes back and forth?
0:13:36 > 0:13:38Yeah, it goes backwards and forwards.
0:13:38 > 0:13:40Grabbing, plucking and pulling
0:13:40 > 0:13:42as the hippo sways its head back and forth,
0:13:42 > 0:13:44cutting that grass down
0:13:44 > 0:13:46like a putting green in a golf course, right?
0:13:46 > 0:13:50The hippo's unique way of eating means they can consume
0:13:50 > 0:13:54a staggering 50 kilos of grass a night.
0:13:54 > 0:13:57Five times what a cow could eat.
0:13:57 > 0:14:00It literally has its head down the whole time.
0:14:00 > 0:14:02- These guys are like vampire lawnmowers.- Heh-heh!
0:14:02 > 0:14:05So this is the hidden world of the hippo.
0:14:05 > 0:14:07Here we were just watching them sleep all day,
0:14:07 > 0:14:09now the animals really actually come alive.
0:14:09 > 0:14:11Yeah.
0:14:11 > 0:14:15The hippos feed for an incredible seven hours straight.
0:14:16 > 0:14:17And it's what happens next
0:14:17 > 0:14:20that makes them the unsung heroes of Africa.
0:14:24 > 0:14:26What goes in must come out.
0:14:34 > 0:14:38Hippos produce up to 27 kilos of dung a day.
0:14:38 > 0:14:40This is what really gets Doug going.
0:14:40 > 0:14:43Oh, watch, watch here!
0:14:43 > 0:14:44Boom!
0:14:44 > 0:14:47- OK, see that shower of dung? - He really showers it.
0:14:47 > 0:14:52And they have a very special way of spreading this dung far and wide.
0:14:52 > 0:14:54They wag their tails.
0:14:54 > 0:14:57And the males have an unusual adaptation
0:14:57 > 0:15:00that gives this muck-spreading an extra boost.
0:15:00 > 0:15:03Hippos have a backward-facing penis,
0:15:03 > 0:15:06probably the weirdest thing about the hippo, right?
0:15:06 > 0:15:09So this backward penis shoots the spray of urine up
0:15:09 > 0:15:12and then he's got a loose, blobby, gooey bit of dung
0:15:12 > 0:15:14shooting out of his rear.
0:15:14 > 0:15:16All of that gets mixed together with this paddle-like tail
0:15:16 > 0:15:18and then it splatters everywhere.
0:15:20 > 0:15:22But this is no laughing matter.
0:15:22 > 0:15:25Through his research, Doug has discovered
0:15:25 > 0:15:28that hippo dung has remarkable properties.
0:15:28 > 0:15:30It's so rich in nutrients,
0:15:30 > 0:15:33it acts as a superfood for life in Africa's rivers.
0:15:35 > 0:15:39The dung become a really important stimulus of life, almost,
0:15:39 > 0:15:42if you will, into this whole food web.
0:15:42 > 0:15:45You lock that piece in and the stuff at the bottom
0:15:45 > 0:15:48begins to sort of work and grow. And then you have herbivores
0:15:48 > 0:15:50that are eating up the algae that grows in the river
0:15:50 > 0:15:52and then fish eating these herbivores. Next thing you know,
0:15:52 > 0:15:55you have fish eagles swooping down, catching and eating fish.
0:15:55 > 0:15:58So, so much of that life sort of springing forth
0:15:58 > 0:16:00from the back of the hippo.
0:16:00 > 0:16:02So, it seems we really must reconsider
0:16:02 > 0:16:04this ruffian of the river banks.
0:16:06 > 0:16:09Thanks to Doug's research, we should now see hippos
0:16:09 > 0:16:12as nature's lawnmowers and fertilisers.
0:16:15 > 0:16:19Their nutrient-rich dung produces food for fish and insect larva
0:16:19 > 0:16:22that live in the rivers, which, in turn, become food
0:16:22 > 0:16:25for other animals all the way up the food chain.
0:16:26 > 0:16:30So, in this way, hippo dung drives the river ecosystem.
0:16:32 > 0:16:34And there is no doubt that Africa would be
0:16:34 > 0:16:36a very different place without them.
0:16:43 > 0:16:44Now, back in the UK,
0:16:44 > 0:16:49Lucy Cooke is at Blackpool Zoo to meet the marine biologists
0:16:49 > 0:16:52who've been investigating how one of the ocean's most effective
0:16:52 > 0:16:55predators catches its prey in pitch-darkness.
0:16:57 > 0:16:59CHEERING AND APPLAUSE
0:16:59 > 0:17:04Sea lions have been wowing us for years with their showmanship,
0:17:04 > 0:17:07but, in the wild, they are even more impressive.
0:17:07 > 0:17:09They are incredible hunters
0:17:09 > 0:17:13that manage to catch their prey at high speed.
0:17:13 > 0:17:17Now, how they manage to achieve this phenomenal feat
0:17:17 > 0:17:21has long been a mystery, but now we know the answer.
0:17:22 > 0:17:24I'm here to meet the sea lion and the scientists
0:17:24 > 0:17:26that have cracked that mystery.
0:17:29 > 0:17:32Sea lions are superb swimmers.
0:17:32 > 0:17:35Capable of 20mph bursts,
0:17:35 > 0:17:38they dive to depths of 180 metres
0:17:38 > 0:17:41and often hunt in dark, murky waters.
0:17:43 > 0:17:47I'm meeting keeper Alyx Milne and one of her ten sea lions.
0:17:50 > 0:17:52THEY LAUGH
0:17:52 > 0:17:56So, this is Anya, she's our nine-year-old Californian sea lion.
0:17:56 > 0:17:59Hello, Anya! Aw! Big kiss!
0:17:59 > 0:18:01I'm going to have a feel of your body.
0:18:01 > 0:18:07Oh, wow! That is incredible, how they are just so muscular.
0:18:07 > 0:18:11- One slippery, lean muscle, isn't she, basically?- She is, yeah.
0:18:11 > 0:18:14She's built to be so robust and streamline
0:18:14 > 0:18:16to be a very good predator.
0:18:16 > 0:18:18So in the wild, she would obviously be able to use
0:18:18 > 0:18:21her flippers for power, to generate the speed,
0:18:21 > 0:18:23and then obviously catching the fish is that neck.
0:18:23 > 0:18:25So they have, like, a darting head movement,
0:18:25 > 0:18:28where they will dart their neck out at the very last second
0:18:28 > 0:18:30to catch that fish and get a tasty bite to eat.
0:18:30 > 0:18:33Until recently, scientists couldn't explain
0:18:33 > 0:18:39how sea lions were able to hunt at great depths and in total darkness.
0:18:39 > 0:18:43How are they able to make that perfectly-aimed strike
0:18:43 > 0:18:45without any night vision?
0:18:46 > 0:18:48After three years of research,
0:18:48 > 0:18:52Alyx and Dr Robyn Grant think they've finally figured it out.
0:18:53 > 0:18:56Their revelations came from studying how Anya performs
0:18:56 > 0:18:59one of the oldest tricks in the sea lion book.
0:18:59 > 0:19:02How does she balance a ball?
0:19:03 > 0:19:05The best way to see Anya in action
0:19:05 > 0:19:08is to film her with a high-speed camera.
0:19:10 > 0:19:12OK, madam, here we go.
0:19:12 > 0:19:14Catch the ball. Amazing!
0:19:16 > 0:19:20- Well done!- Good!- She's starting to test your catching skills.- Exactly!
0:19:21 > 0:19:25More fishy treats for Anya and time for me to look at the footage.
0:19:25 > 0:19:30So, here we've got Anya and the ball slowed down five times.
0:19:31 > 0:19:34Robyn and Alyx have discovered that when the ball rolls,
0:19:34 > 0:19:38it's actually Anya's whiskers that trigger her head to move.
0:19:40 > 0:19:43The whiskers always move just before the head moves.
0:19:43 > 0:19:47So, it's detecting when the ball is about to roll,
0:19:47 > 0:19:49it moves its whiskers and then it moves its head.
0:19:51 > 0:19:54How does it translate to their life in the wild?
0:19:54 > 0:19:56So, what this is showing you is that
0:19:56 > 0:19:59the whiskers are basically always one step ahead.
0:19:59 > 0:20:01When it's getting very close to the fish,
0:20:01 > 0:20:04and the fish is trying to evade, they're able to sense very quickly
0:20:04 > 0:20:08with their whiskers and then change the direction of their body.
0:20:08 > 0:20:11So, what we see with the ball is that it senses it very quickly
0:20:11 > 0:20:12and then it will respond,
0:20:12 > 0:20:16which is very similar to how it would detect a fish, as well.
0:20:17 > 0:20:22As the ball rolls, how her head moves to compensate is triggered
0:20:22 > 0:20:26by her whiskers feeling when the ball is becoming unbalanced.
0:20:28 > 0:20:30In the wild, the whiskers feeling the prey
0:20:30 > 0:20:33would trigger the sea lion's body movement
0:20:33 > 0:20:35to strike and catch the fish.
0:20:37 > 0:20:40It's long been thought that sea lions use their whiskers
0:20:40 > 0:20:42in conjunction with their eyes,
0:20:42 > 0:20:45but Robyn and Alyx believe that because sea lions
0:20:45 > 0:20:47hunt so effectively at depth,
0:20:47 > 0:20:52where it's very dark, they're not using their eyes at all.
0:20:54 > 0:20:57Balancing is just about possible
0:20:57 > 0:21:00if I can watch the object I'm balancing.
0:21:00 > 0:21:04But, if I close my eyes, it's game over.
0:21:04 > 0:21:09Now, we want to find out if Anya our sea lion is able perform
0:21:09 > 0:21:12her balancing act using only her whiskers.
0:21:12 > 0:21:14And, in order to do that,
0:21:14 > 0:21:17we need to repeat the exercise in the pitch-black.
0:21:17 > 0:21:19Now, this is something that Robyn's never done before,
0:21:19 > 0:21:21this is totally new research.
0:21:21 > 0:21:25So we're really excited to see if she's going to be able to manage it.
0:21:30 > 0:21:35As night falls, Alyx leads Anya into position.
0:21:35 > 0:21:38Come on, baby girl. Good job.
0:21:38 > 0:21:41- First, a fishy treat. - Can you see it? There we are.
0:21:41 > 0:21:43ALYX LAUGHS
0:21:43 > 0:21:44For this experiment,
0:21:44 > 0:21:48I'm using a camera which can detect infrared light.
0:21:52 > 0:21:55- OK, are we ready?- We're ready. - All right, lights off.
0:21:55 > 0:21:57'As the lights go out,
0:21:57 > 0:22:01'it's completely dark - apart from the camera screen.'
0:22:02 > 0:22:05OK, here we go, here we go. Will she do it?
0:22:06 > 0:22:09'Will she be able to catch the ball in the pitch-black?'
0:22:13 > 0:22:17She's actually got the ball! I can't believe it! That's amazing!
0:22:18 > 0:22:21'Not only does Anya catch it, incredibly,
0:22:21 > 0:22:23'she's able to balance it.'
0:22:23 > 0:22:26Just see those whiskers, how they're working.
0:22:26 > 0:22:30And you can see that there is movement going on and guiding,
0:22:30 > 0:22:34- isn't there?- It looks very much like what we see in the daytime.
0:22:34 > 0:22:36So, they look like they're moving independently.
0:22:36 > 0:22:40That is astonishing that she's managing to not only catch
0:22:40 > 0:22:44but control the ball. And that really just proves, doesn't it?
0:22:44 > 0:22:46I can't see a thing, she can't see a thing, can she?
0:22:46 > 0:22:49- She has to be doing that just with her whiskers.- Yeah, she does.
0:22:50 > 0:22:53It's so dark that when Anya throws the ball back to Alyx,
0:22:53 > 0:22:56she can't catch it.
0:22:56 > 0:22:58This really is like a super-sense, isn't it, with these whiskers?
0:22:58 > 0:23:02It's as good as eyes that see in the dark, isn't it?
0:23:02 > 0:23:05Yeah. They're using their whiskers as their primary sense.
0:23:05 > 0:23:08So they'll be using them like we would use our eyes,
0:23:08 > 0:23:11whenever they're in the dark and underwater.
0:23:11 > 0:23:13It's a super-sense, a great skill to have.
0:23:13 > 0:23:17- And why she's such a fantastic marine predator.- That's it.
0:23:18 > 0:23:21Lucy's ground-breaking infrared experiment
0:23:21 > 0:23:23has shown for the first time
0:23:23 > 0:23:26that the sea lion's incredible hunting skills
0:23:26 > 0:23:29are all down to its remarkable whiskers.
0:23:36 > 0:23:40Next, we're heading to the South African desert, where Patrick Aryee
0:23:40 > 0:23:43is joining researchers revealing the nocturnal secrets
0:23:43 > 0:23:46of one of its most elusive residents.
0:23:52 > 0:23:54The magnificent Kalahari.
0:23:54 > 0:23:58700,000 square kilometres of arid desert.
0:23:59 > 0:24:01With little water and an extreme climate,
0:24:01 > 0:24:05the animals that live here have evolved extraordinary abilities
0:24:05 > 0:24:09and unique physical adaptations to help them survive.
0:24:09 > 0:24:12I've joined scientists Aliza Le Roux and Matt Petelle.
0:24:15 > 0:24:17We're on a mission to try and find one of the desert's
0:24:17 > 0:24:20most perfectly-adapted animals.
0:24:20 > 0:24:22The bat-eared fox.
0:24:25 > 0:24:28Bat-eared foxes are one of the hardest animals
0:24:28 > 0:24:31in the world to study. They're extremely timid
0:24:31 > 0:24:34and only emerge from their underground burrows at night.
0:24:37 > 0:24:41But Aliza and Matt have finally found a way to get close to them.
0:24:44 > 0:24:46Bribery.
0:24:46 > 0:24:48(Oh, there he is! Look!)
0:24:48 > 0:24:50Over the last 18 months,
0:24:50 > 0:24:53the team have convinced the foxes to trust them,
0:24:53 > 0:24:56with the help of some tasty treats.
0:24:56 > 0:24:59He's using raisins to lure this fox.
0:24:59 > 0:25:01Apparently, they love them.
0:25:03 > 0:25:04Don't want to frighten him.
0:25:04 > 0:25:07What Matt and the team have achieved is extraordinary.
0:25:07 > 0:25:11It's allowing them to finally unlock the bat-eared foxes'
0:25:11 > 0:25:13survival secrets.
0:25:13 > 0:25:18This fox is right here, right in front of us.
0:25:19 > 0:25:22This has been... Isn't he just wonderful?
0:25:22 > 0:25:25I feel like a statue right now. I don't want to move.
0:25:25 > 0:25:28You can move but very slowly.
0:25:28 > 0:25:31OK. How are you?
0:25:31 > 0:25:34And this is the first time that people have been able to get
0:25:34 > 0:25:38this close to these animals on foot.
0:25:38 > 0:25:40It really is quite a special moment.
0:25:40 > 0:25:43Yeah.
0:25:43 > 0:25:47Hello. This is just brilliant.
0:25:49 > 0:25:53One of the adaptations that helps foxes like Baines survive is
0:25:53 > 0:25:57hard to miss - their gigantic ears.
0:25:57 > 0:26:01And they use these to hunt their prey in the darkness,
0:26:01 > 0:26:04which is astonishing considering their favourite prey is about
0:26:04 > 0:26:08one centimetre long and, to most animals, completely silent.
0:26:08 > 0:26:10See how he had his head up like that?
0:26:10 > 0:26:14He's actually listening for the noise of termites.
0:26:14 > 0:26:16See? He's just listening.
0:26:19 > 0:26:20Baines' ears are incredible.
0:26:20 > 0:26:23They can actually pick up the faint crunching sound of
0:26:23 > 0:26:26a termite chewing on dry grass.
0:26:26 > 0:26:30They act like satellite dishes which they can rotate independently
0:26:30 > 0:26:32to gather in sound and amplify them.
0:26:32 > 0:26:36We know that they can pick up the termites' sound and that they can
0:26:36 > 0:26:40actually pinpoint those locations from 50 metres away, at least.
0:26:40 > 0:26:41Incredible.
0:26:41 > 0:26:44See how he just sucked them right up?
0:26:44 > 0:26:46Yeah, his head's just twitching.
0:26:49 > 0:26:52Baines' hearing is far more sensitive than ours.
0:26:52 > 0:26:55And scientists believe they can even detect termites moving
0:26:55 > 0:26:58several feet under the ground.
0:26:58 > 0:27:02- How many termites do you reckon they can get through in a night?- Oh, wow.
0:27:02 > 0:27:04- Thousands, thousands of termites. - Gosh.- And they can go
0:27:04 > 0:27:07from patch to patch, just spent 15 or 20 minutes in an area,
0:27:07 > 0:27:08gobbling them up.
0:27:10 > 0:27:13But it's not all about their ears.
0:27:13 > 0:27:16When termites are not on the menu, bat-eared foxes are highly
0:27:16 > 0:27:21opportunistic, eating other insects, grubs and small mammals.
0:27:23 > 0:27:27To be able to find a range of food successfully in the desert,
0:27:27 > 0:27:30scientists believe that bat-eared foxes need to be natural
0:27:30 > 0:27:34problem solvers, and Matt and Aliza have been putting this to the test.
0:27:37 > 0:27:39Aliza's been out at night,
0:27:39 > 0:27:41presenting them with a challenging puzzle.
0:27:43 > 0:27:44There is the puzzle box.
0:27:46 > 0:27:47To get their favourite raisins,
0:27:47 > 0:27:51they need to either push a lever or pull a rope.
0:27:52 > 0:27:54To the right, you can see where the rope sticks out,
0:27:54 > 0:27:58where they can pull on the string and the lever is on the left,
0:27:58 > 0:27:59- they could potentially push.- OK.
0:27:59 > 0:28:02There we go. There's a fox. Right, here it comes. Yeah.
0:28:02 > 0:28:07Luckily, the fox isn't scared by the unfamiliar object.
0:28:07 > 0:28:09When foraging for scarce food in the desert,
0:28:09 > 0:28:12it pays to always be inquisitive.
0:28:12 > 0:28:16It can smell the food and this is an opportunity that can't be missed.
0:28:16 > 0:28:19Straightaway, he's sniffing and smelling the box.
0:28:19 > 0:28:21He knows something's going on.
0:28:21 > 0:28:23Quite a few raisins in there.
0:28:23 > 0:28:27'But will it solve the problem of how to get to them?'
0:28:27 > 0:28:29Now he's... Oh, brilliant!
0:28:29 > 0:28:34So, that took him about, what, 20 seconds, to hit the first lever.
0:28:34 > 0:28:36Yes.
0:28:36 > 0:28:39And now he's going in the opposite direction. He's at it.
0:28:39 > 0:28:41That is brilliant.
0:28:42 > 0:28:46Our clever candidate refused to be outfoxed.
0:28:46 > 0:28:49And he's worked out how to get his reward in well under a minute.
0:28:52 > 0:28:55- There he goes.- Brilliant. That's awesome.
0:28:57 > 0:29:02So far, Aliza and her team have tested ten bat-eared foxes
0:29:02 > 0:29:06and 80% of the time, they managed to solve the problem.
0:29:07 > 0:29:10Do you think that maybe your puzzle is too simple?
0:29:10 > 0:29:12This is what we are fearing.
0:29:14 > 0:29:17But they still had to figure it out and they still...
0:29:17 > 0:29:19So far, it looks like they show improvement over time
0:29:19 > 0:29:22so there is some sort of learning curve happening.
0:29:26 > 0:29:29The fact they are getting faster at solving the problems
0:29:29 > 0:29:32is evidence of learned behaviour,
0:29:32 > 0:29:36supporting Matt and Aliza's theory that there's more to these
0:29:36 > 0:29:39fantastic foxes than a whopping set of ears.
0:29:41 > 0:29:44It's what between those ears that is the real secret to this
0:29:44 > 0:29:46fox's survival.
0:30:01 > 0:30:03On the other side of the world,
0:30:03 > 0:30:05Giles Clark is in Australia on the trail of
0:30:05 > 0:30:10a rare animal whose anatomy has evolved in a most surprising way.
0:30:13 > 0:30:18After 50 million years of evolution, kangaroos and wallabies are
0:30:18 > 0:30:22perfectly adapted for a life in the Australian outback.
0:30:22 > 0:30:25Five million years ago, a common ancestor of the rock wallaby
0:30:25 > 0:30:29here moved into the rainforest and what resulted is now one of
0:30:29 > 0:30:32the most bizarre animals on the planet.
0:30:34 > 0:30:37It's called Dendrolagus...
0:30:38 > 0:30:41..otherwise known as the tree kangaroo.
0:30:43 > 0:30:46But how does a kangaroo, with its famously large feet and long
0:30:46 > 0:30:50muscular tail, make the leap from living on the ground
0:30:50 > 0:30:51to a life in the trees?
0:30:56 > 0:31:00I'm on my way to the Tree Roo Rescue Centre in Queensland to meet
0:31:00 > 0:31:02Dr Karen Coombes,
0:31:02 > 0:31:06who I hope will shed some light on this mysterious marsupial.
0:31:06 > 0:31:10- Hi, you must be Karen.- I am. Giles, nice to meet you.- Nice to meet you.
0:31:10 > 0:31:13Who is the owner of this magnificent tail?
0:31:13 > 0:31:16This is McKenzie and he's a little baby tree kangaroo
0:31:16 > 0:31:18that we've rescued.
0:31:18 > 0:31:21'Karen is now hand-rearing 10-month-old McKenzie.'
0:31:21 > 0:31:23Look how adorable he is.
0:31:23 > 0:31:26There's a treat. It's your favourite treat.
0:31:26 > 0:31:29'It's only when he emerges that I see how different he is
0:31:29 > 0:31:31'to a normal kangaroo.'
0:31:31 > 0:31:33Amazing.
0:31:33 > 0:31:37'His powerful forearms are more muscular than other kangaroos'.
0:31:37 > 0:31:39'His tail is bigger, to add balance,
0:31:39 > 0:31:42'and his claws longer, to grip branches.'
0:31:45 > 0:31:48His legs do resemble a traditional kangaroo's legs but,
0:31:48 > 0:31:50at the same time, they are different.
0:31:50 > 0:31:53Their back legs are shorter and stockier,
0:31:53 > 0:31:55so they can hop on the ground.
0:31:55 > 0:31:59'But perhaps the biggest reason why they can climb trees is
0:31:59 > 0:32:01'because, unlike their ground-dwelling cousins,
0:32:01 > 0:32:06'who can only hop along on two legs, tree kangaroos can move each
0:32:06 > 0:32:09'of their back legs separately, giving them greater mobility.
0:32:11 > 0:32:13'And for that all-essential grip,
0:32:13 > 0:32:17'the pads on their feet act like climbing shoes.
0:32:17 > 0:32:20'But a youngster still needs to be taught how to use these
0:32:20 > 0:32:21'adaptations to survive.'
0:32:23 > 0:32:25They need to learn how to climb.
0:32:25 > 0:32:27In the wild, they would be doing it 20 metres up
0:32:27 > 0:32:29a tree with their mother.
0:32:29 > 0:32:31And they stay with mum for quite some time,
0:32:31 > 0:32:32once they're even out of the pouch?
0:32:32 > 0:32:35Absolutely. Till they're nearly two and a half
0:32:35 > 0:32:37- or three years of age. - That's a long time.
0:32:37 > 0:32:39It's the longest in the kangaroo family.
0:32:39 > 0:32:43'But if an orphan is to stand any chance of a life back in the wild,
0:32:43 > 0:32:46'they will need a surrogate mother
0:32:46 > 0:32:49'who understands their unique biology.'
0:32:49 > 0:32:52He's holding my finger. He's very thirsty.
0:32:55 > 0:32:59I'm travelling 20 miles, to the edge of the rainforest,
0:32:59 > 0:33:01to meet Margit Cianelli,
0:33:01 > 0:33:04a former zookeeper who is using her knowledge
0:33:04 > 0:33:08of the tree kangaroo's anatomy to prepare orphan joeys for the wild.
0:33:09 > 0:33:12- Was that her?- It could have been.
0:33:17 > 0:33:19- I saw a tail then.- Yeah.
0:33:19 > 0:33:22Baby tree kangaroos are orphaned quite often
0:33:22 > 0:33:27but over the last 40 years, Margit has rescued over 15 of them
0:33:27 > 0:33:31and the latest is making excellent progress in climbing school.
0:33:32 > 0:33:35Wow. Hello, sweetheart.
0:33:38 > 0:33:40- So, this is Kimberly. - Yeah. Isn't she gorgeous?
0:33:45 > 0:33:47I think she's coming down. She has heard you.
0:33:47 > 0:33:51'Kimberly has lived in Margit's house for over two years and
0:33:51 > 0:33:56'she has learned how to use her paws to help her slide down a tree,
0:33:56 > 0:33:59'tail first, just like a wild tree kangaroo.'
0:34:02 > 0:34:05- Good girl, Kimberly.- Oh!
0:34:05 > 0:34:09- Look. This is Giles.- Hello.- Isn't she gorgeous?- Isn't she beautiful?
0:34:10 > 0:34:12Almost home.
0:34:12 > 0:34:16'Following Margit home with a tree kangaroo on her head
0:34:16 > 0:34:19'has to be one of the strangest experiences of my life.
0:34:21 > 0:34:25'That is, until we all sit down to tea together.'
0:34:27 > 0:34:30Just so surreal. Completely normal, I'm sure,
0:34:30 > 0:34:33for you but this is definitely not a typical evening.
0:34:33 > 0:34:36'At less than three years old, in the wild,
0:34:36 > 0:34:40'Kimberly would still be with her mother so while she spends her
0:34:40 > 0:34:44'days in the forest, she spends her nights with her surrogate mum.'
0:34:44 > 0:34:47What's her story? How did she end up in your care?
0:34:47 > 0:34:52She actually fell into a local swimming hole, out of the tree.
0:34:52 > 0:34:57Obviously, she would have drowned. She was only seven months old.
0:34:57 > 0:35:00'All attempts to reunite Kimberly with her mother failed,
0:35:00 > 0:35:03'so Margit took on the job.'
0:35:03 > 0:35:06This is a good exercise.
0:35:06 > 0:35:09'She would need to help Kimberly build up her muscles if she
0:35:09 > 0:35:11'was to get her back into the trees.
0:35:12 > 0:35:16'Once she mastered the basics inside the house, Margit let her loose
0:35:16 > 0:35:20'on her own jungle gym - a handmade climbing frame in the garden.
0:35:21 > 0:35:25'Margit has also been teaching Kimberly what to eat.'
0:35:25 > 0:35:28You're getting your green soup in a minute.
0:35:28 > 0:35:32Maybe Giles can give you your green soup.
0:35:32 > 0:35:36'This soup is her favourite and provides extra fluid and nutrients.'
0:35:36 > 0:35:38Doesn't look like my idea of delicious but...
0:35:38 > 0:35:41She likes it that way.
0:35:41 > 0:35:44'Now, with a taste of what's good for her,
0:35:44 > 0:35:46'she also has to learn what the leaves look like
0:35:46 > 0:35:48'and how to eat them.
0:35:48 > 0:35:51'Unlike her ground-dwelling namesake, who chews up grass,
0:35:51 > 0:35:55'Kimberly's teeth are specially adapted to shear through leaves.'
0:35:57 > 0:35:59You are just an eating machine, aren't you?
0:36:01 > 0:36:04'And, once fed, it's time to hop up to bed.'
0:36:06 > 0:36:09- All right, goodnight. - Sleep well done. Goodnight.
0:36:13 > 0:36:17'A tree kangaroo's sleep pattern is very different to ours.
0:36:17 > 0:36:21'In the wild, the low-calorie diet means they have to eat little
0:36:21 > 0:36:24'and often, so they only sleep in short bursts of up to
0:36:24 > 0:36:25'an hour at a time.
0:36:29 > 0:36:31'The next morning, Kimberly is ready to go.'
0:36:35 > 0:36:38Hello. Morning.
0:36:39 > 0:36:43I'm just fascinated in the way in which gets around.
0:36:43 > 0:36:45It's the sort of half walk, half hop.
0:36:45 > 0:36:49When she hops, the tail never touches the ground.
0:36:49 > 0:36:51See?
0:36:53 > 0:36:57'Margit wants Kimberly to spend less time walking on the kitchen floor
0:36:57 > 0:37:00'and more time climbing in the trees.
0:37:00 > 0:37:04'Eventually, she wants her to return to the wild but before this
0:37:04 > 0:37:08'can happen, Margit must be sure Kimberly knows how to use
0:37:08 > 0:37:11'her brilliantly adapted body to climb 45 metres,
0:37:11 > 0:37:14'up to the forest canopy and find food for herself.'
0:37:19 > 0:37:20Good girl.
0:37:20 > 0:37:23'We are attaching a tiny, lightweight camera
0:37:23 > 0:37:25'to Kimberly's tracking collar.'
0:37:25 > 0:37:26OK.
0:37:26 > 0:37:29'This will give us the rare opportunity to see the world
0:37:29 > 0:37:31'from her perspective and, importantly,
0:37:31 > 0:37:33'whether she has what it takes to be wild again.'
0:37:35 > 0:37:36Good girl.
0:37:36 > 0:37:39OK. We'd better go.
0:37:39 > 0:37:44'Off the ground, it becomes clear just how agile Kimberly really is.
0:37:44 > 0:37:47'She's perfectly adapted to a life in the trees.'
0:37:57 > 0:38:01I'm mesmerised, just how quickly she got up the tree.
0:38:04 > 0:38:06She knows how to distribute her weight.
0:38:06 > 0:38:106.5 kilos, and she's just standing literally on twigs.
0:38:10 > 0:38:12Look at her balancing.
0:38:12 > 0:38:14It's extraordinary.
0:38:17 > 0:38:19She's definitely at home in a tree.
0:38:19 > 0:38:21She knows where she wants to go.
0:38:24 > 0:38:27'To reach the tastiest leaves at the top of the tree,
0:38:27 > 0:38:31'Kimberly will have to climb the height of a six storey building
0:38:31 > 0:38:34'and way beyond what we can see from ground level.'
0:38:36 > 0:38:38We are going to have a look.
0:38:38 > 0:38:41'When we review the Kimberly cam footage later that night,
0:38:41 > 0:38:44'it reveals the surprising secrets
0:38:44 > 0:38:47'of her extraordinary anatomy in action.'
0:38:47 > 0:38:49- Look how high she is.- Yeah.
0:38:49 > 0:38:52Almost makes me dizzy when she looks down. Yeah.
0:38:53 > 0:38:55Right up in the canopy.
0:38:55 > 0:38:58It's her speed along the branches that's so impressive,
0:38:58 > 0:39:02compared to her awkward movements on the ground.
0:39:02 > 0:39:04Man, she moves around so quickly.
0:39:04 > 0:39:06I must say, I'm a bit surprised by that.
0:39:06 > 0:39:10- She's more active than I... - Than you had anticipated?- Yeah.
0:39:11 > 0:39:14'And in the ten hours she was up there, Kimberly proves that
0:39:14 > 0:39:17'she has also learned which leaves she needs to eat
0:39:17 > 0:39:19'in order to survive.'
0:39:19 > 0:39:23- You can see she's eating here. You can hear it.- It's just amazing.
0:39:23 > 0:39:25And she's so fussy.
0:39:25 > 0:39:28She picks and sniffs lots of them but only eats certain ones.
0:39:29 > 0:39:33'Margit's remarkable understanding of a tree kangaroo's unique
0:39:33 > 0:39:37'anatomy has enabled her to teach Kimberly and over 15 other
0:39:37 > 0:39:40'orphans the skills that they need to survive in the wild.'
0:39:42 > 0:39:44You can't help but feel she's nearly there.
0:39:44 > 0:39:47It shouldn't be too much longer and she will be making that
0:39:47 > 0:39:50choice to stay out. "I'm going to stay out tonight, Mum."
0:39:50 > 0:39:51Yes. And I'm ready for it.
0:39:51 > 0:39:53I'm proud of her.
0:39:53 > 0:39:55I love her and she can do it all.
0:39:55 > 0:39:58Even though she didn't have a real mum.
0:39:58 > 0:40:00Oh, she's got a real mum...
0:40:00 > 0:40:03- You just don't have a big tail. - Thanks!
0:40:08 > 0:40:13Still in Australia, but nearly 2,000 miles south, lives a very peculiar
0:40:13 > 0:40:18animal, whose anatomy has baffled scientists for hundreds of years.
0:40:22 > 0:40:26And on hand to investigate its remarkable method of hunting,
0:40:26 > 0:40:29is marine biologist Shanta Barley.
0:40:32 > 0:40:36I joined ecologist Josh Griffiths on the Yarra River, just outside
0:40:36 > 0:40:40Melbourne, to track down the famous oddity that lurks in these waters.
0:40:43 > 0:40:45It was once considered a primitive mammal.
0:40:47 > 0:40:51But new research is revealing that this animal is the ultimate
0:40:51 > 0:40:53predator in the creeks and rivers of Australia.
0:40:53 > 0:40:55I'm hoping to find a platypus.
0:40:56 > 0:41:00The egg-laying platypus is one of the oddest animals on the planet.
0:41:00 > 0:41:04It looks like a cross between a duck, a beaver and an otter.
0:41:04 > 0:41:08It's estimated there could be tens of thousands in the wild
0:41:08 > 0:41:09but numbers are dwindling
0:41:09 > 0:41:12as a result of severe drought and pollution.
0:41:12 > 0:41:16They're most active at night and it's almost impossible to spot one,
0:41:16 > 0:41:18let alone catch one.
0:41:18 > 0:41:21But if anyone can catch one, Josh can.
0:41:21 > 0:41:23He's been monitoring the success of the wild population
0:41:23 > 0:41:25in this area for six years
0:41:25 > 0:41:28and has become a leading expert on these animals.
0:41:28 > 0:41:30If you had a good look at the rocks,
0:41:30 > 0:41:32you'd see some of the things that platypus are eating.
0:41:32 > 0:41:37Some of the insect larvae, small crustaceans, worms.
0:41:37 > 0:41:39That's what they're looking for, little invertebrates like that.
0:41:39 > 0:41:42Using its bill, the platypus needs to hoover up
0:41:42 > 0:41:46a third of its body weight in food every single night.
0:41:46 > 0:41:48And it does all of this in the dark.
0:41:49 > 0:41:52With the net in place, and night drawing in,
0:41:52 > 0:41:54all we can do now is wait.
0:41:56 > 0:42:00I've heard that the way that this extraordinary creature hunts
0:42:00 > 0:42:01is similar to a shark,
0:42:01 > 0:42:06and, as a marine biologist and shark expert, I'm fascinated to know more.
0:42:07 > 0:42:11We know that they can detect the electrical impulses of animals
0:42:11 > 0:42:15moving underwater, so those tiny little insects that we saw earlier,
0:42:15 > 0:42:19their muscle contractions create a minute electrical impulse.
0:42:19 > 0:42:20It must be absolutely tiny.
0:42:20 > 0:42:23It's tiny, it's something that a lot of our really sensitive equipment
0:42:23 > 0:42:25can't even pick up.
0:42:25 > 0:42:31After six hours, we finally spot movement in the net.
0:42:31 > 0:42:33We got anything? We've got something!
0:42:33 > 0:42:35I tell you what, I tell you what...
0:42:35 > 0:42:40- There he is.- It's the most amazing thing. He's holding on, isn't he?
0:42:40 > 0:42:43Yeah, they're really strong little creatures.
0:42:46 > 0:42:48And that is a little male.
0:42:48 > 0:42:50We finally got one.
0:42:50 > 0:42:52'To prevent him from getting stressed,
0:42:52 > 0:42:54'we put the platypus in a bag.
0:42:54 > 0:42:57'And while we record his size, weight and general health,
0:42:57 > 0:43:01'it's an opportunity for me to get a close look at his remarkable bill
0:43:01 > 0:43:03'which detects these electrical signals,
0:43:03 > 0:43:06'allowing him to hunt so effectively in the dark.'
0:43:06 > 0:43:09- So he's just poked his bill out of the hole in the bag.- Oh, wow.
0:43:09 > 0:43:12- Can I touch it?- Yeah, it's very different to what people expect.
0:43:12 > 0:43:14Oh, my gosh.
0:43:14 > 0:43:18It's not hard like a duck's bill, it's actually quite soft to touch.
0:43:18 > 0:43:19Wow. It's so soft.
0:43:19 > 0:43:23You can see the little pores that are all through the bill.
0:43:23 > 0:43:25They're very fine.
0:43:25 > 0:43:28- There's thousands of them across the bill.- Yeah.
0:43:28 > 0:43:32'Around 40,000 tiny bumps speckle the bill.
0:43:32 > 0:43:35'These are the receptors that detect minute electrical currents.
0:43:35 > 0:43:38'This is how the platypus can pick out a single worm wriggling
0:43:38 > 0:43:42'on a rock in a pitch-black running river.'
0:43:42 > 0:43:45And what's really jumping out at me is the concentration is really high
0:43:45 > 0:43:47on the edges of the bill,
0:43:47 > 0:43:50and that's exactly what you get in the hammerhead shark.
0:43:50 > 0:43:54With that really weird head, they also have electro-receptors, really,
0:43:54 > 0:43:59in high densities right on the edges of the head.
0:43:59 > 0:44:02'Astonishingly, this bill contains more than ten times the number
0:44:02 > 0:44:05'of electrical receptors as the hammerhead shark.'
0:44:06 > 0:44:07So, in some ways,
0:44:07 > 0:44:11a platypus is actually a more effective hunter than the shark.
0:44:11 > 0:44:14Well, I like to think they're superior, anyway! OK.
0:44:15 > 0:44:17'With the checkup complete,
0:44:17 > 0:44:20'it's time to return this supreme hunter to the river.'
0:44:21 > 0:44:25- Let's let him get back to doing what he does best.- Yeah.
0:44:25 > 0:44:27'I've examined the platypus's bill...'
0:44:27 > 0:44:29There he goes!
0:44:29 > 0:44:31'..but I've yet to see it in action.' Go on, go on!
0:44:35 > 0:44:37So, I'm heading to Healesville Sanctuary,
0:44:37 > 0:44:40a haven for threatened, native-Australian species
0:44:40 > 0:44:4240 miles from Melbourne.
0:44:42 > 0:44:45It's home to a female platypus called Yamacuna.
0:44:46 > 0:44:48So acrobatic.
0:44:53 > 0:44:57It's feeding time for Yamacuna. On the menu, blood worms.
0:44:59 > 0:45:02The blood worms are alive, so they're emitting electrical signals.
0:45:02 > 0:45:05When Yamacuna detects those signals,
0:45:05 > 0:45:10she shuts down her eyes and her ears and lets her bill take over.
0:45:16 > 0:45:19It might look like haphazard snuffling for food,
0:45:19 > 0:45:20but this is precision hunting.
0:45:20 > 0:45:23Although her eyes and ears are closed,
0:45:23 > 0:45:26her bill's electro-receptors come into play.
0:45:26 > 0:45:28As she swings her head from side to side,
0:45:28 > 0:45:32she's casting a 3-D invisible net.
0:45:32 > 0:45:34It picks up the worms' electrical signals.
0:45:35 > 0:45:39Yamacuna's bill also detects the minuscule pressure waves
0:45:39 > 0:45:41produced by the wriggling worms.
0:45:41 > 0:45:43As the intensity of the electrical signals
0:45:43 > 0:45:44and pressure waves increases,
0:45:44 > 0:45:47she knows exactly how close the worms are.
0:45:47 > 0:45:51And this allows Yamacuna to strike with deadly accuracy.
0:45:55 > 0:45:57A few minutes is all it takes
0:45:57 > 0:46:00to track, locate and eat hundreds of worms.
0:46:00 > 0:46:03For me, the comparison with sharks is fascinating.
0:46:03 > 0:46:07Both detect electrical signals and pressure waves.
0:46:07 > 0:46:09The platypus even has similar body movements
0:46:09 > 0:46:13to a hammerhead shark when hunting, swaying its head from side to side.
0:46:15 > 0:46:18The shark needs sight and smell to home in on its prey.
0:46:18 > 0:46:23But, amazingly, the platypus hunts without these senses.
0:46:23 > 0:46:24Just like the shark in our oceans,
0:46:24 > 0:46:28the platypus is master of its environment.
0:46:28 > 0:46:32Thanks to its extraordinary bill, it's the perfect predator.
0:46:35 > 0:46:389,000 miles away, zoologist Lucy Cooke
0:46:38 > 0:46:40is in the Costa Rican jungle
0:46:40 > 0:46:45where new research is revealing that the sloths' famed laziness
0:46:45 > 0:46:48could be the secret to its survival.
0:46:52 > 0:46:55These are four-month-old baby sloths, and they'll become
0:46:55 > 0:47:00one of the most successful animals in the jungle once they grow up.
0:47:01 > 0:47:06These babies are learning to climb on a rocking chair,
0:47:06 > 0:47:09which is genius, because it mimics the movement of a tree.
0:47:12 > 0:47:16I've studied these eccentric animals for over five years
0:47:16 > 0:47:19and we really shouldn't underestimate them.
0:47:19 > 0:47:21So, a lot of people think that sloths,
0:47:21 > 0:47:24because they're so slow and lazy,
0:47:24 > 0:47:29that they are somehow evolutionary losers.
0:47:29 > 0:47:34But, actually, sloths are extremely successful.
0:47:37 > 0:47:40Sloths are secretly one of the most abundant mammals
0:47:40 > 0:47:42in the Costa Rican rainforest.
0:47:42 > 0:47:46New research is revealing the extraordinary adaptations
0:47:46 > 0:47:47behind their success.
0:47:51 > 0:47:53Professors John Pauli and Zach Peery,
0:47:53 > 0:47:56and their team of sloth specialists, are carrying out
0:47:56 > 0:48:00one of the biggest ever studies of this little-known creature.
0:48:02 > 0:48:06Oh, there!
0:48:06 > 0:48:11That is so cool. Literally lying in a tree, having a nap.
0:48:11 > 0:48:13Just like a sloth should be.
0:48:13 > 0:48:16It is just about the most chilled out-looking animal
0:48:16 > 0:48:17you've ever seen in your life.
0:48:19 > 0:48:23One of the sloth's key survival tricks is what it eats.
0:48:23 > 0:48:26John and Zach discovered that because they do so little,
0:48:26 > 0:48:30for their size, sloths need to consume less calories
0:48:30 > 0:48:32than any other mammal.
0:48:32 > 0:48:35The amount of energy a sloth needs to live
0:48:35 > 0:48:36on a day is really, really low.
0:48:36 > 0:48:40- It's about 140 kcal per day.- Wow!
0:48:40 > 0:48:44That's like the same as a packet of crisps. That's, like, nothing.
0:48:44 > 0:48:49Even though the leaves they eat have very little nutritional value,
0:48:49 > 0:48:52it's not a problem for the sloth.
0:48:52 > 0:48:55Everything about them is perfectly evolved
0:48:55 > 0:48:58to live off this tiny amount of energy.
0:48:58 > 0:49:01This is really like the classic sloth pose,
0:49:01 > 0:49:05this hanging upside down like this.
0:49:05 > 0:49:07They eat upside down, they sleep upside down,
0:49:07 > 0:49:09they give birth upside down.
0:49:09 > 0:49:13And their hair even grows backwards
0:49:13 > 0:49:17so that the rain will just drip off them.
0:49:17 > 0:49:20This is the most energy-efficient way to be,
0:49:20 > 0:49:24because they're hanging, they're just using these muscles
0:49:24 > 0:49:27in order to hang on.
0:49:27 > 0:49:30But the sloth's clever tricks don't end there.
0:49:32 > 0:49:35By lounging around all day, high in the trees,
0:49:35 > 0:49:38sloths are safe from ground predators like jaguars,
0:49:38 > 0:49:42but they're still vulnerable to aerial hunters like the harpy eagle.
0:49:44 > 0:49:48'But, again, sloths have found a solution.'
0:49:48 > 0:49:51It's coming down to see us!
0:49:51 > 0:49:52'They're green.
0:49:52 > 0:49:56'Which means they merge with the trees.
0:49:56 > 0:50:00'And this camouflage is the result of a strange relationship
0:50:00 > 0:50:04'between the sloth and a tiny creature hidden in its fur.'
0:50:06 > 0:50:09Hello, mister.
0:50:11 > 0:50:14Wow! It's a male. Oh, wow!
0:50:14 > 0:50:17Have you given this one a name?
0:50:17 > 0:50:20- 992 is the number of his radio. - Really?
0:50:20 > 0:50:22We don't have a name for him.
0:50:22 > 0:50:24- What about Cyril?- Cyril works.- Yeah.
0:50:25 > 0:50:29- You want to hold him? - Yeah, wow. Fantastic.
0:50:30 > 0:50:34Cyril is covered in a particular kind of moth.
0:50:35 > 0:50:40These moths are only found in sloths. They're found nowhere else.
0:50:40 > 0:50:45They depend entirely on the sloth for their entire existence.
0:50:45 > 0:50:50The moths depend on the sloth for all their home comforts and food.
0:50:50 > 0:50:53And, for a long time, it was assumed that it was only the moths
0:50:53 > 0:50:56that benefited from this arrangement.
0:50:56 > 0:50:59But, thanks to John and Zach's recent discovery,
0:50:59 > 0:51:02we now know there's something in it for the sloth, too.
0:51:02 > 0:51:04When these moths die,
0:51:04 > 0:51:08they actually fertilise the fur within the sloth
0:51:08 > 0:51:09and they create nitrogen
0:51:09 > 0:51:13that helps the algae that you see on their fur to grow.
0:51:13 > 0:51:16- The moths themselves are like making compost?- That's right.
0:51:16 > 0:51:19- That helps keep the sloth green. - That's exactly right.
0:51:20 > 0:51:23The more moths that inhabit a sloth's fur,
0:51:23 > 0:51:25the greener and more camouflaged it can become.
0:51:27 > 0:51:30This clever relationship means they don't have to outrun predators,
0:51:30 > 0:51:33they simply disappear.
0:51:35 > 0:51:37These ingenious adaptations
0:51:37 > 0:51:40means sloths are thriving in the rainforest,
0:51:40 > 0:51:42all without lifting a finger.
0:51:46 > 0:51:48He's not in a hurry.
0:51:50 > 0:51:55He walks a little way, takes a rest, and he walks a bit more.
0:51:57 > 0:52:00And I think us busy, bipedal apes
0:52:00 > 0:52:03have probably got quite a lot to learn from them.
0:52:03 > 0:52:06About spending less energy.
0:52:18 > 0:52:21So far, we've had new insights into the amazing ways
0:52:21 > 0:52:24animals adapt to their environments.
0:52:24 > 0:52:27And we've seen how some of those adaptations can be crucial
0:52:27 > 0:52:28for the planet.
0:52:28 > 0:52:31And, with more knowledge of an animal's biology,
0:52:31 > 0:52:32we can look after them better,
0:52:32 > 0:52:35and help ensure their future survival.
0:52:37 > 0:52:41Teaching a captive animal the secrets of survival in the wild
0:52:41 > 0:52:43is a tough challenge for conservationists.
0:52:45 > 0:52:49I'm back in the French Alps to see how one man's understanding
0:52:49 > 0:52:51of an eagle's amazing anatomy
0:52:51 > 0:52:55is taking him closer to his dream of returning it to the wild.
0:52:57 > 0:53:00Falconer Jacques Olivier Travers believes that,
0:53:00 > 0:53:02after nine months of training,
0:53:02 > 0:53:06his white-tailed eagle Victor is almost ready to be freed.
0:53:08 > 0:53:11Victor's mastered lesson one, the art of basic flight.
0:53:12 > 0:53:16And he's well on the way with lesson two, how to hunt.
0:53:17 > 0:53:20But before he can become a truly wild eagle,
0:53:20 > 0:53:24Victor must prove he can use his highly-tuned anatomy
0:53:24 > 0:53:26to complete lesson three,
0:53:26 > 0:53:30advanced flight at high altitude.
0:53:30 > 0:53:32We're in the ski resort of Morzine,
0:53:32 > 0:53:36where Victor's on a warm-up flight ahead of his final challenge.
0:53:37 > 0:53:40He flies easily down the sheltered slope.
0:53:44 > 0:53:47But his future will depend on whether he can master the skills
0:53:47 > 0:53:51to navigate the changes in wind speed and direction
0:53:51 > 0:53:53in the open mountains.
0:53:53 > 0:53:57Up here, in wild weather, mistakes could be fatal.
0:53:57 > 0:54:00We need to take him up to 1,500 metres.
0:54:00 > 0:54:03This is the very limit of the eagles' natural range.
0:54:05 > 0:54:07- Everything all right there? - I think so.
0:54:07 > 0:54:11- Very good.- Where shall we put him down?- Yeah...
0:54:14 > 0:54:19Jacques Olivier has trained Victor to follow him wherever he goes.
0:54:19 > 0:54:20But, eventually,
0:54:20 > 0:54:25the eagle will have to face this ultimate flying test alone.
0:54:25 > 0:54:28By skiing quickly away from him, Jacques Olivier knows that Victor
0:54:28 > 0:54:32will have to face up to these very tough conditions.
0:54:35 > 0:54:38And if that's not enough for a student eagle to contend with,
0:54:38 > 0:54:40he'll have the added challenge of having to avoid
0:54:40 > 0:54:43the overhead cables of the ski lift.
0:54:43 > 0:54:46It may all be too much to ask for today.
0:54:48 > 0:54:49Hup, hup!
0:54:54 > 0:54:55Here he goes.
0:54:55 > 0:54:59But Victor launches his 4kg body into the air
0:54:59 > 0:55:02using the sheer power of his wing beats for lift
0:55:02 > 0:55:05and the primary flight feathers at the tips of his wings
0:55:05 > 0:55:07for balance and direction.
0:55:09 > 0:55:13Once up, Victor stretches his wings to glide horizontally,
0:55:13 > 0:55:16enabling him to use as little energy as possible.
0:55:17 > 0:55:20To cope with the changes in air pressure,
0:55:20 > 0:55:24he controls his flight, making small, finely-tuned adjustments
0:55:24 > 0:55:27to his wing feathers and even the angle of his head.
0:55:32 > 0:55:36Now, as you can see, the wind is bad. It's difficult for him to stay.
0:55:36 > 0:55:38He looks like he knows he's doing!
0:55:38 > 0:55:43Yeah, you can see that he flies so slowly because the wind is bad,
0:55:43 > 0:55:45he has to control his flight. It's good, it's good.
0:55:47 > 0:55:51But the descent will be the toughest challenge of all.
0:55:51 > 0:55:55Air currents become unstable the closer to the ground he gets.
0:55:55 > 0:55:58And ski lift cables are everywhere.
0:55:58 > 0:56:01Victor must make increased adjustments to control his flight.
0:56:03 > 0:56:06He'll need this control if he's ever to catch prey
0:56:06 > 0:56:08in this tough environment.
0:56:10 > 0:56:13Yeah, he's coming back now, it's perfect.
0:56:18 > 0:56:20Hup! Victor, hup!
0:56:20 > 0:56:23Even in these conditions, Victor's able to slow himself down
0:56:23 > 0:56:26from a 60 mile an hour dive
0:56:26 > 0:56:29and land precisely on Jacques' hand.
0:56:29 > 0:56:32- Hey! Victor!- Nice work, Victor.
0:56:32 > 0:56:34Yeah, yeah, nice work.
0:56:34 > 0:56:36Because, today, as you can see,
0:56:36 > 0:56:38it's not very good weather conditions for flying.
0:56:38 > 0:56:40At the top of the mountain the wind was bad,
0:56:40 > 0:56:43he was pushing down but he worked hard to turn
0:56:43 > 0:56:46in bad weather conditions to follow us.
0:56:46 > 0:56:49- Now he's ready to go into the wild, for sure.- Really?
0:56:49 > 0:56:52- Yeah.- So he's got to that point in his training with you
0:56:52 > 0:56:56that he's as strong a flier as he needs to be to survive?
0:56:56 > 0:56:59Yeah, and now for flying, for hunting, he's perfect.
0:57:01 > 0:57:04Introducing captive-bred animals back into the wild
0:57:04 > 0:57:08has to be one of the hardest things in wildlife conservation.
0:57:08 > 0:57:10There are just so many different challenges
0:57:10 > 0:57:12to identify and then overcome.
0:57:13 > 0:57:16But when there's a man who's prepared to go the extra mile
0:57:16 > 0:57:20and a bird who's prepared to follow him up every mountain,
0:57:20 > 0:57:23then I don't think it's hard to believe that a few years from now,
0:57:23 > 0:57:27there could be wild white-tailed eagles flying in the Alps again.