Animals With The Strangest Survival Powers (4K Documentary)

追加: 2026-05-30

[00:00:01]In this episode, in the jungles of Costa Rica, we discover why sloths are encouraging moths to [music] set up home in their fur.

[00:00:13]In Australia, we meet a kangaroo that appears to be far happier climbing [music] trees than hopping through the outback.

[00:00:22]In [music] the Kalahari Desert, we get up close to a fox with hearing so sensitive it can detect insects burrowing deep underground.

[00:00:32]And we'll reveal the survival secrets of what is quite possibly the world's oddest looking creature.

[00:00:43]But first, in the French Alps, a remarkable relationship between a man and a white-tailed eagle is for the first time revealing a deeper understanding of the species so that captive [music] bred eagles can be taught everything they need to know to survive in the wild. From teaching them how to fly in dangerous terrain to teaching them how to catch fish for themselves.

[00:01:09]This unlikely pairing is not only [music] changing the way we think about birds, but also helping secure the survival of the species from extinction.

[00:01:22]With a wingspan of almost 2 1/2 m, the white-tailed eagle is [music] the largest eagle in Europe.

[00:01:30]These aerial masters are born [music] with impressive anatomy. Their wings are built to soar on thermals. Their eyesight so sharp they can spot prey on the ground with pinpoint accuracy. And to bring home their target, they have powerful talons capable of a deadly snatch and grab, whether that be with fish or small mammals.

[00:01:55]Until recently, scientists believed it would be impossible to teach captive bred eagles enough skills to successfully hunt and survive on their own.

[00:02:06]But professional falconer Jacqu Olivier Trav is turning that thinking on its head. He's developed a technique that is starting to show signs that it can be done. That captive bred eagles can be taught to master the secrets of survival.

[00:02:23]If these bird are trained to fish, trained to fly, they have more chance to survive into the wild. After one or two years, you can have babies in the wild, which is the goal.

[00:02:39]White-tailed eagles are skilled hunters, but the hunters became the hunted.

[00:02:50]Seen as a threat to livestock in Britain and as vermin in France, they were wiped out in both countries by the early 20th century.

[00:03:01]Now, the only white-tailed eagles in France are in averies or zoos.

[00:03:08]I discover this bird in a book. I say, "Wow, I never see this bird. I want to see one." And I have to wait for a long time, more than 20 years to see my first one. But when I discover this bird, I fall in love with him. And I I thought I have to do something for this bird because it disappear because of us, because we kill all of them.

[00:03:27]So, Jacqu Olivier decided he needed to do something. But where do you begin?

[00:03:35]Well, it may seem obvious, but it's with flying. And for a man to teach an eagle how to fly, Jacqu Olivier has to think like an eagle and fly like one, even if that means taking to the air with a paraglider.

[00:03:54]Flying in captivity is very different to flying in the wild. A bird who is born in captivity knows how to go from point A to point B. [music] But to use the thermal, to use the wind, to use the mountains, everything. The parag glider is the best things.

[00:04:11][music] I did many many big flights from Mlon from to cross the channel between England and France uh in Africa to prove that my bird fly like a wild one.

[00:04:23]It seems the Eagles not only view Jacqu Olivier as their mentor on the ground, but in the air too. They form a strong bond. What is amazing, it's the three, four weeks when you start to fly, I'm better than him. But after 1 month, they fly so well that I can't follow them.

[00:04:44]A tiny harness camera on their back gives Jacqu Olivier an amazing insight into what it's like to be an eagle.

[00:04:52]>> The first time you on the back of a bird, you can feel what he feels.

[00:04:58]Scientists start to think that okay, we are right that we [music] can teach a bird to fly and to hunt. And now they start to support us. And we expect that in [music] one or two years we can do the first real try into the wild to reintroduce adult burn in captivity that we teach them to fly onto him.

[00:05:16]With the basics of wild flight successfully learned, Jacqu Olivier realized that if he could now just teach his birds how to hunt for fish, the goal of releasing eagles to the wild would be within reach.

[00:05:30]But that is easier said than done because eagles learn by imitation, copying how their parents hunt. And it turned out that his captive bred eagles are frightened of the water.

[00:05:44]At the beginning, I thought, oh, it's a fish eagle. He would like to go on the water. But no, it's scared by the water because he never see the water in his life. And I had to teach him that it's not dangerous, that he can go, that the prayer in the water. Uh it's why it's very important to teach them.

[00:06:00]>> So Jacqu Olivier started with the basics using safe unthreatening environments.

[00:06:07]Small pool bigger pool lake and small piece of fish real fish live fish. It's different step. It's a sophisticated movement.

[00:06:17]He have to control his wings movement, his legs movement, talent movement in the same second. It's very quick.

[00:06:26]Eventually, the eagles begin to realize what they needed to do in [music] order to get food for themselves.

[00:06:33]>> He can catch live fish in a training pool, but the last step will [music] be live fish in a big lake because when he knows to do that, he don't need [music] me and he will go back to the wild.

[00:06:45]Jacqu Olivier's unique [music] bond with his birds is vital for preparing the way for a new life in the wild. [music] But to be sure they can cope with any situation, they have one last lesson to learn before they can be set free.

[00:07:00]Advanced flight. In the toughest part of an eagle's natural habitat, the mountains.

[00:07:13]Up here, the birds must be able to cope with treacherous strong winds and other extreme weather conditions.

[00:07:21]We'll join him later in the program when one of his eagles takes on the ultimate flying challenge.

[00:07:32]Next, 4,000 m away in Kenya, we're on the trail of something rather more cumbersome.

[00:07:40]The hippopotamus.

[00:07:45][music] Hippos are the largest vegetarians on the planet, capable of munching through 50 kg of vegetation a day with relentless machine-like efficiency.

[00:07:57]It's a lot of food hoovered up by each animal. But scientists have recently discovered that hippos may well give back more to their environment than they take.

[00:08:12]>> [music] >> If ever there was an animal with an image problem, it's these guys.

[00:08:19]They weigh the same as a family car, but come with the attitude of a 32 ton truck. The hippopotamus is renowned as the most dangerous animal in Africa.

[00:08:30]Today, conservationist Giles Clark has come to see the work of Dr. Doug McCauley. He's been studying these hippos for the past 5 years.

[00:08:41]People talk about hippos as being one of the most aggressive, most dangerous animals in Africa, but they really feel comfortable in the water. If you don't get in the water, they'll continue just to keep to themselves. But, uh, we come down on a boat right through here, it would be a pretty big mess.

[00:08:57]>> Okay.

[00:08:58]>> Wow.

[00:08:59]>> It's always wise to keep a safe distance from hippos, especially because on land, they can run at 20 m an hour.

[00:09:13]There they go, J. That's your welcome here to the Hippopot.

[00:09:19]>> Such an incredible noise.

[00:09:21]>> It's communication.

[00:09:23]>> They're letting each other know that there's something strange here on the riverbank. They communicating about threat right now, you and I. They're uh they're a little worried or want.

[00:09:32]>> They've got nothing to worry about in this or not me anyway.

[00:09:38]There's a hippo over here doing the yawn display. But those yawns are not about waking up.

[00:09:47]The yawn-like behavior is designed to show everyone who's boss by displaying those imposing ivory tusks. The tusks are only used for fighting. As vegetarians who graze, the job of grinding up food falls to the huge mers at the back of their mouths.

[00:10:07]During the day, hippos seemingly do very little. But Doug's [music] research is revealing that this is far from the case. Because while hippos wallow, they're actually playing a vital role [music] in supporting the whole ecosystem.

[00:10:24]And it's all to do with eating.

[00:10:28]Hippos prefer to dine alone or in small groups, splitting from the main pod and traveling a short way down the river.

[00:10:35]There they leave the water to graze on the food of choice, grass, but to avoid the heat [music] of the strong African sun, their favorite time to dine is after dark.

[00:10:52]The plan is to observe what they get up to using a newly designed thermal camera that can film with no light.

[00:11:00]It can detect the heat from an animal's body up to 6 miles away. And it's something Doug has not been able to try before. Now, >> this tool is amazing.

[00:11:11]One of the reasons why there's just so little known about the hippo is because it's so hard to see them at night.

[00:11:16]>> You wouldn't want to be >> traing around in that scrubby vegetation at night looking for them. No.

[00:11:23]>> Whoa. There. There. There. There.

[00:11:24][music] Okay.

[00:11:25]>> Wow. Look at him.

[00:11:28]>> Our thermal camera gives some revealing insight into their nighttime [music] activities.

[00:11:32]>> Look how it lights up.

[00:11:33]>> Yeah. So, almost looks like she's blotchy there.

[00:11:36]>> Yeah. It sort of looks like camouflage almost, doesn't it? First time I've seen this in a thermal [music] camera.

[00:11:43]>> The blotches are almost certainly thermal windows. flushed areas on the skin that allows them to cool down.

[00:11:53]Overheating can be a huge problem for hippos, especially when walking on land.

[00:12:02]But hippos are not the only diners around tonight.

[00:12:08]And spooked, the hippos demonstrate how quickly they can move when they need to.

[00:12:16]When things have calmed down an hour later, the camera finally picks up two hippos grazing amongst the trees.

[00:12:24]>> So, hang on a minute. I think we have a hippos here.

[00:12:26]>> Yeah. Okay. Oh, wow. Look, >> their 60 cm wide mouth gives them an ability to graze in a way that is very different from other herbivores.

[00:12:36]>> It's all lips. They're using those big horny lips to grab grass there from the understory. Rip it as see as it heads goes back and forth. goes backwards and forwards, >> grabbing, plucking, and pulling as the hippo sways its head back and forth, >> cutting that grass down like a like a putting green in a golf course, right?

[00:12:54]>> The hippo's unique way of eating means they can consume huge amounts of grass in one night. Five times what a cow would eat.

[00:13:04]>> It literally has his head down the whole time.

[00:13:06]>> These guys are like vampire lawnmower styles. So, this is the hidden world of a hippo. Here we were just watching him sleep all day. Now that now the animals really actually come alive.

[00:13:18]>> The hippos feed for 7 hours straight and it's what happens next that makes them the unsung heroes of Africa because what goes in must come out.

[00:13:42]And this is what really gets Doug excited.

[00:13:47]>> Oh. Oh, watch. Watch here. Boom.

[00:13:51]>> Okay. See that shower of dung?

[00:13:53]>> He really showers it.

[00:13:54]>> They have a very special way of spreading this dung far and wide. They wag their tails. And the males have a unique adaptation [music] that gives this mukspreading technique even more of a boost. Hippos have a backward-facing [music] penis. Probably the weirdest thing about the hippo, right? So, this backward penis shoots the spray of urine up and then he's got a loose, globby, gooey bit of dung shooting out of his rear. All of that gets mixed together with this paddle-like tail and then it splatters everywhere.

[00:14:26]>> Doug has discovered that this unique behavior has widespread benefits to the environment. The dung is packed with nutrients that acts as a superfood for all life in and around the river.

[00:14:41]The dung becomes a really important stimulus of life almost, if you will, into this whole food web. You lock that piece in and the stuff at the bottom begins to sort of work and grow and then you have herbivores that are eating up the algae that grows in the river and then fish eating these herbivores. Next thing you know, you have fish eagles swooping down catching and eating fish.

[00:15:01]So, so much of that life sort of springing forth from the back of the hippo.

[00:15:07]>> Thanks to Doug's [music] research, we now know that hippos are not just takers. As nature's mobile mukspreaders, they give back, fertilizing the land and the rivers [music] to produce food for fish and for insect lavi that live in the water. All of which in turn will become food for other animals up the food chain. They truly are a life force of Africa's rivers.

[00:15:37][bell] Next, at Blackpool Zoo in the UK, zoologologist Lucy Cook is marveling at another creature who likes to wallow in the water.

[00:15:49]For years, the public and scientists alike have been impressed at how sea lions are able to perform incredible feats of skill that even humans find it hard to master.

[00:16:02]But now, thanks to the research being done here by keeper Alex Mil and Dr. Robin Grant, the secrets of their skills are finally being unraveled.

[00:16:12]secrets that not only make sea lions superb entertainers, but which also makes them one of the most effective and deadly hunters of the deep.

[00:16:26]By studying one of the classics of sea lion skills, balancing a ball on the nose and using the latest high-speed cameras to capture it, it's become clear just how important their whiskers are to perceiving the environment around them.

[00:16:40]can throw the ball in for Gina >> today. Sea lion Anna is demonstrating what she can do.

[00:16:50]>> Okay, madam. Here we go. Catch the ball.

[00:16:54]Amazing.

[00:16:57]>> Well done. [laughter] Very good.

[00:16:58]>> Started to test your catches.

[00:17:00]>> Exactly.

[00:17:04]Robin and Alex have discovered that when the ball rolls, it's Anna's whiskers that trigger her head to move.

[00:17:13]The whiskers always move just before the head moves. So, it's detecting when the ball is about to roll, it moves its whiskers and then it moves its head.

[00:17:24]>> How does it translate to their life in the wild? What this is showing you is that the whiskers are basically always one step ahead. When it's getting very close to the fish and the fish is trying to evade, they're able to sense very quickly with the whiskers and then change the direction of the body. So, what we see with the ball is that it senses it very quickly and then it all responds, which is very similar to how it would detect a fish as well. [music] >> In the wild, the whiskers detecting the prey would trigger the sea lion's body movement to strike and catch fish. even when hunting at high speed or in near darkness 180 m down in the ocean.

[00:18:05]So this got Dr. Robin thinking, do they need to see? Could they hunt using just their whiskers alone?

[00:18:19]To find out, she turned to the ball trick again, >> though this time at night, using special infrared cameras to capture what happens in the dark.

[00:18:30][music] >> Okay, we [music] ready?

[00:18:35]>> Ready.

[00:18:36]>> All right, lights off.

[00:18:38]>> It had always been thought that sea lions used their whiskers in conjunction with their eyes to successfully [music] hunt. But would this prove otherwise?

[00:18:47]Here we go. Will she do it?

[00:18:55]>> She's actually got the ball. I can't believe it. That's amazing.

[00:18:59]>> Incredibly, Anna is able to balance the ball just as she did in the daylight.

[00:19:05]>> She can't see a thing, can she? She has to be doing that just with her whiskers.

[00:19:08]>> Yes, [music] she does. They're using their whiskers as their primary sense.

[00:19:12]So they'll be using them like we would use our eyes whenever they're in the dark and [music] underwater.

[00:19:18]>> It's a super sense. Great skill to have and why she's such a fantastic marine predator.

[00:19:23]>> That's it.

[00:19:24]>> This simple infrared [music] experiment has shown for the first time that sea lion's efficient hunting [music] skills are all down to the smallest of anatomical adaptations, their whiskers.

[00:19:42]>> [music] >> Next, in South Africa, a group of researchers are on the hunt. They are trying to discover the nocturnal secrets of a rather elusive creature.

[00:19:56]Biologist Patrick Aie is joining them to find out more.

[00:20:02]This is the Kalahari Desert. 700,000 km of semi-arid savannah.

[00:20:11]With little water and an extreme climate, the animals that live here have had to evolve unique physical adaptations in order to survive.

[00:20:24]Alisa Laroo and Matthew Patel are here to study the batared fox.

[00:20:32]Batared foxes are extremely [music] timid and difficult to get close to.

[00:20:37]They only emerge from their underground burrows at night. But Eliza and Matt have found a way to win their trust using bribery.

[00:20:49][music] Oh, there he is. Look. Over the last 18 months, the team have managed to build a relationship with the foxes by offering raisins as gifts. This fox is right here, right in front of us.

[00:21:11]Being able to get this close to a fox is helping Matt and Alisa finally understand the secrets of their survival.

[00:21:22]>> Isn't he just wonderful? I kind of feel like a statue right now. I don't want to move.

[00:21:26]>> Yeah, you can move, but move very slowly.

[00:21:28]>> Okay. How are you?

[00:21:32]>> And this is the first time that people have been able to get this close to these animals on foot.

[00:21:39]It really is quite a special moment.

[00:21:41]>> Yeah.

[00:21:43]Hello.

[00:21:45]This is just brilliant.

[00:21:49]One of the adaptations that helps bat-eared foxes to survive here is hard to miss. It's their gigantic ears.

[00:21:57]They use their ears to hunt in the dark.

[00:22:00]And given their favorite prey are termites, which are only about 1 cm long and are completely silent to most animals. It's an astonishing capability.

[00:22:10]>> You see how he had his head up like that? He's actually listening for the noise of termites. See, he's just listening.

[00:22:18]>> The bat-eared fox's ears are so sensitive they can pick up the faint crunching of termites chewing on dry grass. Their ears act like satellite dishes and can rotate independently to gather in and amplify sounds.

[00:22:34]>> We know that they can pick up the termite sound and that they can actually pinpoint those locations from 50 m away at least.

[00:22:41]>> Incredible.

[00:22:44]See how he just sucked him right up?

[00:22:46]>> Yeah, his head's just twitching.

[00:22:49]>> Researchers have found that their hearing is so sensitive they can easily detect burrowing termites several feet underground.

[00:22:59]>> How many termites do you reckon they can get through in a night?

[00:23:03]>> Oh wow. Uh thousands. Thousands of termites. And they can go from patch to patch and just spend 15, 20 minutes in an area gobbling them up.

[00:23:11]But to be successful in the desert, bat-eared foxes need more than just termites on the menu. They supplement their diet with insects, grubs, and even small mammals.

[00:23:25]Finding a range of food in a harsh environment like this is no easy task.

[00:23:31]So, scientists believe they need to be natural problem solvers in [music] order to survive here.

[00:23:38]It's something Matt and Alisa have been able to put to the test and filmed some remarkable nocturnal behavior.

[00:23:47]There [music] is the puzzle box.

[00:23:50]>> The puzzle box contains some raisins, but to get to them, the fox has to pull a rope or push a lever.

[00:23:57]>> To the right, [music] you can see where the rope sticks out where they can pull on the string. And the lever is on the left. They could potentially push.

[00:24:04]>> Okay, >> there we go. There's a fox right here.

[00:24:06]He comes. Yep.

[00:24:07]>> The fox isn't scared by the unfamiliar object. When foraging for scarce food in the desert, it pays to always be inquisitive. It can smell the food, and this is an opportunity that can't be missed.

[00:24:21]>> Straight away, he's sniffing and smelling the box. You know something's going on. [music] >> Quite a few raisins in there.

[00:24:28]>> But will it solve the problem of how to get at them?

[00:24:32]>> Yeah, he's got Oh, [snorts] brilliant.

[00:24:35]So that took him about what 20 seconds to hit the first lever.

[00:24:39]>> Yes. And now he's going the opposite direction. He's at it.

[00:24:44]>> That is brilliant.

[00:24:47]>> The clever candidate refused to be outf foxed. And in well under a minute, he works out how to get his reward.

[00:24:57]>> There we go.

[00:24:59]>> That's awesome. [music] Alisa and her team have tested 10 batared foxes. A remarkable 80% of them managed to solve the problem.

[00:25:11]So far, it looks like they show improvement over time. So, there is some sort of learning curve happening.

[00:25:19]>> [music] >> The foxes are getting faster at getting to the raisins, which is evidence of intelligent, learned behavior, supporting Matt and Alisa's theory that there's more to [music] these creatures than just an incredible set of ears.

[00:25:35]It's also what's between those ears that seems to be the secret to their survival.

[00:25:47]Next, we're on the other side of the world in Australia. It's a continent not unknown for its unique and rather strange animals. [music] And none are stranger than perhaps the macropods, such as kangaroos and walabbees, both of which developed large feet, strong, long tails, and an ability to hop huge distances through the outback.

[00:26:14]But head into the lush Australian rainforest and you might be surprised to discover there is a kangaroo that has evolved to live in trees.

[00:26:26]It's known as the tree kangaroo.

[00:26:31][music] Today, conservationist Charles Clark is meeting Margaret Chiianelli. She spends her time raising orphan tree kangaroos to help them get back into the wild.

[00:26:44]>> Was that her?

[00:26:45]>> It could have been.

[00:26:47]>> We're about to meet Kimberly.

[00:26:50]>> I saw a tail then.

[00:26:52]>> Yeah. Yeah.

[00:26:54]>> Margaret is a former zookeeper and over the years as a surrogate mom has successfully released 15 tree kangaroos back into the wild.

[00:27:07]>> Wow.

[00:27:09]Hello, sweet.

[00:27:11]>> So, this is Kimberly.

[00:27:13]>> Yeah. Isn't she gorgeous?

[00:27:18]>> I think she's coming down.

[00:27:20]>> She's heard you.

[00:27:21]>> Kimberly has lived in Marget's house for over 2 years.

[00:27:24]>> Good girl.

[00:27:26]>> And she's learned how to use [music] her paws to help her slide down a tree.

[00:27:31]>> Tail first.

[00:27:33]>> Just like a wild tree kangaroo. Good girl, Kimi.

[00:27:38]>> Look, this is Charles.

[00:27:40]>> Hello.

[00:27:41]>> Isn't she gorgeous?

[00:27:42]>> Isn't she beautiful?

[00:27:44]>> Almost home.

[00:27:47]>> Walking home with a kangaroo on your head is just an everyday experience for Marget.

[00:27:54]And so, it seems is sitting down to have tea with one.

[00:28:01]Just so surreal. Completely normal, I'm sure, for you, but this is definitely not a typical evening. [laughter] >> Kimberly is just 2 and 1/2 years old. In the wild, she would stay with her mother until around the age of three, the longest in the kangaroo family.

[00:28:17]So, while she spends her days in the forest, she still prefers to spend her nights with her surrogate mom.

[00:28:24]>> What's her story? How did she end up in your care?

[00:28:26]>> She actually fell into a local swimming hole.

[00:28:30]>> Oh.

[00:28:30]>> Out of a tree. and obviously would have drowned. I mean, she was only seven months old.

[00:28:36]>> All attempts to reunite Kimberly with her mother failed, so Marget took on the job.

[00:28:43]>> This is a good exercise.

[00:28:45]>> She would need to help Kimberly build up her muscles if she was to get back into the trees.

[00:28:51]Once she'd mastered the basics inside the house, [music] Margaret let her loose on her own handmade jungle gym.

[00:29:00]Margaret has also been teaching Kimberly what to eat.

[00:29:05]>> You get me your green soup in a minute.

[00:29:08]Maybe Charles can give you your green soup.

[00:29:11]>> This green soup is Kimberly's favorite and provides her with extra fluid and nutrients.

[00:29:18]>> Doesn't look like my idea of delicious, but [music] >> she likes it.

[00:29:25]Next, she has to learn what the leaves she will need to eat in the wild look [music] and smell like. You're >> just an eating machine.

[00:29:36]>> And when she's fed, it's time to hop up to bed.

[00:29:40]>> All righty. Good night.

[00:29:42]>> Sleep well then.

[00:29:43]>> Good night.

[00:29:46][music] >> A tree kangaroo's sleep pattern is very different to ours. In the wild, their low calorie diet means they eat little and often. So, they only sleep in short bursts of up to an hour at a time, and that makes getting a good night's rest [music] not that easy for Margaret.

[00:30:09]>> Hello.

[00:30:10]>> Hello, Missy.

[00:30:11]>> Good morning. I'm just fascinated in the way in which she gets around. It's this sort of half walk, half hop. When she hops, the tail never touches the ground.

[00:30:23]>> See how she >> unlike her ground dwelling kangaroo cousins who can only hop, tree kangaroos can move their legs independently. It gives them [music] greater mobility.

[00:30:41]But Margaret wants Kimberly to spend less time walking on her kitchen floor and more time climbing up in the trees.

[00:30:48]Good girl.

[00:30:52]>> Today, a tiny lightweight camera is being attached [music] to Kimberly's tracking collar.

[00:30:58]>> Okay.

[00:30:59]>> This will give an opportunity to see the world from Kimberly's perspective and importantly for Margaret to see if she has what it takes to survive in the wild.

[00:31:11]>> Okay, [music] we better go.

[00:31:15]Off the ground, it [music] becomes clear just how agile Kimberly really is.

[00:31:21]>> Oh, look at her go. [music] >> She's perfectly adapted to life in the trees.

[00:31:31]>> I'm mesmerized just how quickly she got up the trail.

[00:31:38]>> She knows [music] how to distribute her weight. 6 and 12 kilos and she's just standing literally on [music] twigs.

[00:31:44]Yeah, look at her balancing.

[00:31:47]>> It's extraordinary.

[00:31:51]>> Well, she's definitely at home in the tree. She knows where she wants to go.

[00:31:58]>> To reach the tastiest leaves at the top of the tree, Kimberly will have to climb the height of a sixstory building. It's way beyond what can be seen from ground level.

[00:32:10]We all got to have a look.

[00:32:11]>> Reviewing the camera [music] footage later that night reveals the surprising secrets of Kimberly's abilities.

[00:32:21]>> Look how high she is.

[00:32:24]>> Almost makes me dizzy when she looks down.

[00:32:25]>> Yeah.

[00:32:27]>> Right up in the canopy.

[00:32:29]>> Her speed along branches is so impressive compared to her awkward movements on the ground.

[00:32:36]>> Man, [music] she moves around so quick.

[00:32:38]I must say I'm a bit surprised by that.

[00:32:40]She's more active than know >> than you anticipated.

[00:32:46]>> Kimberly was up in the trees for almost 10 hours during [music] which time she more than proved she was ready for life in the wild. You >> can see that she's eating here. Can hear it. [music] >> It's just amazing.

[00:32:59]>> And she's so fussy. She picks and sniffs lots of them, but only eats certain [music] ones.

[00:33:07]It takes Margaret around 2 years to teach her orphans all the skills they need to survive. But for Kimberly, her days at school are nearly over.

[00:33:17]>> You can't help but feel she's nearly there. Shouldn't be too much longer. And she'd be making that choice to stay out.

[00:33:24]I'm going to stay out tonight, Mom.

[00:33:25]>> Yes. And I'm ready for it. [music] I am proud of her. I love her. And she can do it all. Even though she didn't have a real mom.

[00:33:34]>> Oh, she's got a real mom.

[00:33:36]You just don't have a big tail.

[00:33:39]>> Thanks.

[00:33:44]>> Next, we're still in Australia, but 2,000 mi south on the Yara River, just outside Melbourne.

[00:33:53]Marine biologist Shanta Barley is joining ecologist Josh Griffiths in search of a very strange animal. An animal so unusual that when reports [music] of its anatomy first emerged around 200 years ago, many were convinced it was a hoax.

[00:34:14]Described back then as a duck that was part beaver and which laid eggs, it's not hard to see why.

[00:34:22]They're here to find the duck build platypus.

[00:34:30]If you want to knock one of those, >> it's difficult to see them by day. They prefer to hunt at night. So Josh sets traps and will wait for nightfall in order to [music] study them more closely. Josh has been researching platypus here for the past 6 years and is discovering just how perfectly adapted they are to hunt and survive in these creeks. If you had a good look at the rocks, you'd probably see some of the the things that platypus are eating.

[00:34:57]Some of the insect larae, small crustations, worms, and that's what they're looking for. Little invertebrates like that.

[00:35:05]Platypus need to eat a third of their body weight in food every single night.

[00:35:11]That's an awful lot of lavi and worms to find in the dark.

[00:35:15]With the net in place, all they need to do now is wait.

[00:35:24]Surprisingly, Platypus managed to find food in the dark in a very similar way to how sharks detect and hunt for their food.

[00:35:34]We know that they can detect the electrical impulses of animals moving underwater. So, those tiny little insects that we saw this afternoon, their muscle contractions creates a minute electrical impulse.

[00:35:46]>> It must be absolutely tiny.

[00:35:47]>> It's tiny. It's something that a lot of our really sensitive equipment can't even pick up.

[00:35:53]>> After waiting for 6 hours, finally the net moves.

[00:35:57]>> You got anything?

[00:35:58]>> I'll tell you what.

[00:35:59]>> We got something.

[00:36:00]>> I'll tell you what.

[00:36:02]>> There he is.

[00:36:04]>> Most amazing thing. He's holding on, isn't he?

[00:36:07]>> Yeah. They're really strong little creatures.

[00:36:12]>> And that is a little male.

[00:36:15]We finally got one.

[00:36:17]>> Josh quickly puts the platypus in a bag to make it feel safer. It helps calm it down and stops it from becoming stressed.

[00:36:26]Its size, weight, and general health are recorded to monitor [music] the population. It's also a unique opportunity to take a close look at its remarkable bill, which can detect electrical signals and which allows it to hunt so effectively.

[00:36:42]>> So, he's just poked his bill out of the the hole in the bag. Yeah. Can I touch it there?

[00:36:46]>> Yeah. It's It's very different to what people expect.

[00:36:48]>> Oh my gosh.

[00:36:50]>> It's not hard like a duck's bill. It's actually quite soft to touch.

[00:36:54]>> Wow. So soft.

[00:36:56]>> You can see the little pores that are all through the bill.

[00:36:59]>> They're very fine.

[00:37:01]>> There's thousands of them across the bill.

[00:37:04]>> Around 40,000 tiny bumps speckle the bill. These are the receptors that detect minute electrical currents.

[00:37:12]Equipped with these, the platypus can pick out a single worm wriggling on a rock in a pitch black river.

[00:37:18]Astonishingly, when compared to the hammerhead shark, the platypus has more than 10 times as many electrical receptors.

[00:37:27]>> Okay, >> with Josh's checkup complete, it's time to return this supreme hunter back to the [music] river.

[00:37:35]>> Let's let him get back to doing what he does best. Yeah, >> it's intriguing to see the bill of a wild platypus close up, but to see it in action, Shanta heads to observe a platypus in a much more controlled environment.

[00:37:53]Melbourne's Heelsville [music] sanctuary is a haven for threatened Australian species, and it's also home to a female platypus called Yamakuna.

[00:38:04]So acrobatic.

[00:38:07]>> It's feeding time. On the menu today are blood worms.

[00:38:14]Although only a few cm long and extremely thin, as with any living creature, the blood worms are emitting tiny electrical signals.

[00:38:24]When Yamakuna detects those signals with her bill, she goes into hunting mode and without using her eyes or her hearing, lets her bill guide her to the prey.

[00:38:37]As Yamakuna swings her head from side to side, it's as though she's casting a 3D invisible net, which picks up the electrical signals from the worms.

[00:38:48]Her bill is also detecting minuscule pressure waves produced by the wriggling. And as the intensity of those signals increases, Yamakuna knows exactly how close the worms are.

[00:39:02]A few minutes is all it takes to track, locate, [music] and eat hundreds of worms. The comparison with sharks is fascinating. Both can detect electrical signals and pressure waves. [music] But where a shark also uses vision to home in on its prey, the platypus can hunt in total darkness using only the receptors on its bill.

[00:39:26]How surprising then, an animal early explorers thought was part duck, part beaver, is actually one of the most technically advanced hunters on the planet.

[00:39:40]On the other side of the world, in the rainforests [music] of Costa Rica, another remarkable creature has found a very clever way to ensure its survival by using camouflage.

[00:39:52]It's the sloth.

[00:39:55]Sloths are one of the most abundant mammals here, but they are not easy to spot. [music] Today, zoologologist Lucy Cook is joining a team of researchers who thankfully know how to find them.

[00:40:09]Professors John Paulley and Zach Perryi have been carrying out one of the biggest studies ever made of this little known creature, [music] looking at the extraordinary adaptations that allow sloths to thrive in this environment.

[00:40:23]>> Oh, there.

[00:40:26]That is so cool. Literally lying in a tree having a nap just like a sloth should be.

[00:40:36]He's not in a hurry.

[00:40:38]>> [bell] >> He walks a little way. He takes a rest.

[00:40:46]He walks a bit more.

[00:40:51]By taking their time to go about their business, they burn fewer calories than [music] any other mammal of similar size.

[00:41:01]The amount of energy a sloth needs to live on a day is really, really low.

[00:41:05]It's about 140 kilo calories per day.

[00:41:08]>> Wow. That's like the same as a packet of crisps. That's like nothing.

[00:41:14]>> The leaves that sloths prefer to eat have very little nutritional value. So, [music] by conserving energy, they are able to survive on tiny amounts of food each day.

[00:41:28]But being slow does have its downside.

[00:41:32]It makes them hugely vulnerable to predators [music] like jungle cats and aerial hunters like the harpy eagle. So these sloths have developed a clever [music] use of camouflage.

[00:41:45]It's coming down to see it.

[00:41:47]>> The sloth is green because it's covered in algae and perfectly matches [music] its surrounding environment.

[00:41:57][music] Hello, mister.

[00:42:08]>> Wow. It's a male.

[00:42:11]>> Oh, wow.

[00:42:12]>> Have you given this one a name?

[00:42:15]>> 992 was the number of his radio.

[00:42:17]>> Really?

[00:42:18]>> But we we don't have a name for him.

[00:42:19]>> What about Sirill?

[00:42:20]>> Sirill works.

[00:42:21]>> Yeah.

[00:42:23]>> You want to hold him?

[00:42:24]>> Yeah.

[00:42:24]>> Wow. Not only is Sirill covered in algae, but on closer inspection, there are hundreds of tiny moths that he allows to live in his fur.

[00:42:35]>> These moths are only found in sloths.

[00:42:38]They're found nowhere else. Uh they depend entirely on the sloth for their entire existence.

[00:42:45]>> For a long time, it was assumed that it was only the moths that benefited from this arrangement. But John and Zach's research is finding this is definitely a two-way street.

[00:42:56]>> When these moths die, they actually fertilize the fur within the sloth and they create nitrogen that helps the algae that you see on their fur to grow.

[00:43:07]>> The moths themselves are making compost.

[00:43:09]>> That's right.

[00:43:10]>> That helps keep the sloth green.

[00:43:12]>> That's exactly right.

[00:43:14][music] The more moths that live on a sloth, the greener and more camouflaged it will become.

[00:43:24]This clever relationship [music] means that sloths don't have to outrun predators. They simply disappear.

[00:43:40]Next, we're back in France following the extraordinary story of how a bird that was eradicated from the country over a 100red years ago is on the verge of being reintroduced.

[00:43:53]Professional falconer Jacqu Olivier Traver is the man behind that plan.

[00:43:59]Through [music] his special relationship with white-tailed eagles, he's managed to develop a technique that is hoped [music] will allow captive bred eagles to be released and to survive in the wild.

[00:44:12]The technique requires 9 months of one-on-one training.

[00:44:18]First, he teaches the eagles the basics of wild flying over difficult terrains.

[00:44:25]Then, how to hunt for themselves.

[00:44:28]But before the eagles are considered ready for release, the birds must pass one last test. Flying in difficult weather conditions high in the mountainous ski resort of Morine.

[00:44:42]Jacqu Olivier is taking his latest pupil up to,500 [music] m for the final test.

[00:44:49]It's on the upper extreme of an eagle's natural habitat. But if a bird that has been hand raised can fly here, it can fly anywhere.

[00:44:59]When you are in mountain during winter, it's a bad environment because the wind come down the mountains and push vehicle in the valley. He can't fly very well.

[00:45:08]He have to do big effort to stay in the mountain to control his flight and it's one of the most difficult exercise that I can do with a bird. But when he's able to do that, it means that he fly like a wild one.

[00:45:21]This eagle is trained to fly to Jacqu Olivier on command.

[00:45:26]But up [music] here with high crosswinds and the added challenge of having to avoid the potentially fatal overhead cables, the stakes are high.

[00:45:38]Up.

[00:45:45]The eagle launches its 4 kg body into the air, using its sheer power and primary flight feathers at the tips of the wings to become airborne.

[00:46:14]>> [music] >> As you can see, the wind is bad. It's difficult for him to stay.

[00:46:29]You You see, you can see that he flies so slowly because the wind is bad. You have to control his flight. No, it's good. It's good.

[00:46:38]The rapid [music] descent is the toughest challenge yet.

[00:46:43]Air currents become unstable the closer it gets to the ground.

[00:46:50]These conditions are exactly like those the eagles will have to master if they're ever able to catch prey on their own.

[00:47:00]Yeah, he's coming back now. It's perfect.

[00:47:08]Up, Victor. Up.

[00:47:09]>> Even in these blustery conditions, the eagle is able to slow himself down from a 60 mph dive to land precisely on Jacques Olivier's hand.

[00:47:19]>> Hey, Victor.

[00:47:24]>> Nice work. Because today, as you can see, it's not very good weather condition for flying on the top of the mountain. The wind was bad. He was pushing down, [music] but he he worked hard to turn in bad weather condition.

[00:47:35]Follow us. Now he's ready to go into the wild for sure.

[00:47:42]Introducing captive bred animals to the wild successfully is one of the hardest things to do in wildlife conservation.

[00:47:51]But through the dedication of one man and his extraordinary relationship and understanding of his birds, the white-tailed eagle could soon once again be flying free in the French Alps.

[00:48:19][music]