A Glimpse into the Lives of Otters | BBC Earth

0:00 To stay warm and active,

0:02 they must each catch at least a kilogram of fish every day.

0:15 As they enter the water, their dense, oily fur traps air close to their bodies.

0:24 Like an underwater blanket, it insulates them from the icy water.

0:36 Ice now covers all but a few small sections of the river.

0:44 So, many of the fish here are now out of sight.

0:54 Luckily, otters can hold their breath for 8 minutes at a time,

0:59 enabling them to hunt far beneath the frozen surface.

1:09 Throughout winter, as the wind blows and temperatures change,

1:15 the ice holes on the river shift.

1:18 So, every day the otters must check each opening one by one.

1:31 Their efforts eventually pay off.

1:40 They may be small, but these fish are packed with valuable protein and fat.

1:47 A nutritious meal that other predators cannot reach while the rivers are frozen.

2:03 But the otters' success hasn't gone by unnoticed.

2:09 Bald eagles look on jealously.

2:16 They too need fish to survive.

2:20 But they have no way to reach them under the ice.

2:34 Time for a new strategy.

2:39 Theft.

2:43 Bald eagles are armed with razor-sharp beaks

2:48 and strong talons that could easily injure an otter.

2:53 By traveling together, these two can work as a team.

3:05 As long as this river stays frozen,

3:08 the otters will have to endure this aerial harassment.

3:14 In the swamp lands of Brazil,

3:21 the giant otter pups have really gained confidence.

3:36 Now a couple of months old, all three are tentatively exploring beyond the den.

3:45 They've still got a lot to learn.

3:53 Giant otters highly social, spending their whole lives in a tight-knit family.

4:02 They work together protecting the territory,

4:05 watching out for predators, and helping out with the babysitting.

4:20 Pups need to learn how to contribute to family life.

4:29 Today's crucial lesson will be a big step on the road to adulthood,

4:34 toilet training, otter style.

4:39 An adult leads the way, with the pups eagerly looking on.

4:45 Giant otters use communal latrines,

4:49 meaning the whole family do their business in the same spot.

4:54 It's a vital way to mark the territory,

4:59 and there's a crucial technique involved.

5:04 Key to getting it right is all about rubbing the scent in.

5:09 It creates an almighty stink that will see off any other otter family.

5:19 Now, it's the three pups' turn.

5:26 One plucks up the courage to give it a go.

5:30 He thinks about going all the way to the top, but chickens out.

5:40 Not exactly the right spot.

5:49 And no hint of robbing.

5:52 But, it's a step in the right direction.

5:56 An adult takes over.

5:59 If you want a job done properly, do it yourself.

6:11 The pups need to get the hang of the toilet

6:13 etiquette if they're going to start contributing to family life.

6:21 These three are learning fast,

6:24 but they've still got an important skill to master.

6:27 Soon, they'll need to hunt for their own food.

6:33 Mastering tricky fishing techniques is a key

6:36 right of passage for many water babies.

6:47 A visiting male otter woos a female on the lake's shore.

6:59 But, she seems a little distracted.

7:08 Her two pups are nearby.

7:11 They're about 10 weeks old, and the time is right to lead them from the holt.

7:23 Males are not above stealing food from cubs.

7:27 So, she makes it very clear that he is not going to be joining them.

7:51 This female grew up on the lake.

7:54 So, she knows where to take the cubs for a very special trip.

8:09 Yellowstone cutthroat trout are massing in the mouth

8:12 of a stream that feeds the lake.

8:15 They're preparing for their annual spawning.

8:24 But, the trout must wait.

8:26 The stream is still running fast.

8:28 Too turbulent to lay their eggs.

8:35 It's a nervous time for them.

8:37 And for good reason.

8:50 This osprey has a brood to feed and will be back.

9:11 Now, the otters are here, too.

9:17 She chooses her moment to lead the pups upstream.

9:26 Then, leaves them to watch.

9:28 And gives them a lesson in hunting.

9:57 A large trout like this, full of eggs, is a trophy catch.

10:18 She chews its tail first to make sure the fish can't get away.

10:27 While the pups are still demanding milk,

10:30 the mother otter will often keep the whole fish for herself.

10:34 The pups are happy enough with caviar.

10:51 As the flow becomes slow enough for the trout to lay eggs,

10:54 there is a brief window of opportunity to spawn

10:57 before the river gets too shallow to swim upstream.

11:06 The female digs a trough with sinuous flicks of her body,

11:11 and the attending male fertilizes the eggs as they are laid.

11:23 Millions of new lives.

11:28 Just as they've done before,

11:30 Diablo and the family have to deal with this threat.

11:38 All the adults start to harass the caiman.

11:45 As the cubs keep their distance,

11:47 Sophia takes her position at the front, sizing up the caiman.

11:54 Others move in to try to distract it.

12:11 Diablo once again moves in from behind and goes for the tail.

12:26 The caiman refuses to back down, and then begins to fight back.

12:58 The cubs panic and follow the adults right into the middle of the fight.

13:03 They're in extreme danger now, so the adult otters step up the assault.

13:15 The caiman tries to head for the safety of the bushes, but it's too late.

13:20 He's outnumbered.

13:22 The otters seize the moment.

13:35 Incredibly, they overpower the caiman.

13:37 Some holding it down, others biting it in the head.

13:51 After nearly an hour of brutal fighting, it's all over.

14:11 The caiman may be dead, but Charlie needs to know if all the otters are okay.

14:20 It doesn't take long to realize two of the cubs haven't survived the fight.

14:34 Stuck in the middle of the action like this, the young,

14:37 inexperienced cubs were no match for such a powerful and aggressive predator.

14:55 The truce between otters and caiman has, for a brief moment, been broken.

15:05 What impresses Charlie the most, though,

15:07 is the incredible show of family bonds and physical strength the otters brought

15:11 together to kill the caiman and eliminate the threat of it from their land.

15:16 Have cubs.

15:31 Seeing otter cubs in the wild like this is extremely rare.

15:41 Charlie counts six tiny cubs, a record number,

15:45 making a grand total of 15 family members.

15:56 Diablo and his mate Sophia are certainly playing their part in helping

16:00 to maintain the survival of giant otters in this part of the Amazon.

16:04 But so many cubs will be quite a handful.

16:07 The family will certainly have their work cut out keeping them out of danger.

16:12 The first thing the cubs need to learn is how to swim.

16:16 So this family outing is actually a swimming lesson.

16:21 Strangely, otter cubs don't actually like water.

16:24 So lessons like this one are essential.

16:33 There's one cub in particular who catches the eye.

16:37 Not because he's muddier than the others,

16:38 but because he really doesn't like the water.

16:48 Despite mom's best efforts,

16:50 all he wants to do is get back to the warmth and security of the den.

17:11 The other cubs all seem to be enduring their swimming lesson.

17:14 Some even look like they're starting to get the hang of it.

17:19 But this little cub's just not having it.

17:22 So in the end, there's nothing for it but to just

17:25 pick him up and dunk him in the water.

17:41 As cubs, all of the otters here are

17:44 given names to help any scientists studying them.

17:48 It seems fitting to give this cub a name appropriate to Lake Salvador.

17:52 So Charlie calls him Dali.

18:10 Even with the protection of a big family,

18:12 the early months of a cub's life can be the most perilous.

18:16 Learning to swim is just the first danger to overcome.

18:24 Only around a third of all these giant otter cubs will make it to adulthood.

18:31 At this age, the cubs tire easily.

18:34 So it's not long before their swimming lesson is over

18:37 and they're taken back to the warmth and safety of the den.

18:58 All this activity attracts Montana's trout fishing experts.

19:08 The otter family.

19:10 Mother is taking her young pups out for a master class.

19:29 Otters can find fish in darkness using sensitive whiskers.

19:35 The pups cling tight picking up the technique.

19:41 Like mother bear, she's a skilled teacher and will look after

19:45 her pups until next year when they can make it on their own.

20:01 It's that slash of red beneath the gills that gives cutthroat trout their name.

20:16 As she dines her pups tuck into the nutritious

20:19 orange eggs gobbling them up like sweets.

20:37 The smell of fresh fish is in the air.

20:49 The bears quickly pick up the scent of the otters meal.

20:57 In shallow water like this it should be easy.

21:02 But trout are slippery customers.

21:19 Success.

21:22 Following mother's lead, Archie jumps right in.

21:38 But just like climbing trees, it takes practice.

21:49 Mother knows this annual feast won't hang around.

22:02 At last, Archie's got the hang of it.

22:06 So does Luke.

22:11 The cubs' first trout dinner is a rare, high-protein meal.

22:17 They've also learned to gobble food down quickly.

22:28 Their feast hangs thick in the air.

22:33 The scent might attract grizzlies.

22:41 Their mother doesn't take chances and leads them back to the canyon.

22:52 Most of the trout escape, leaving the stream seeded with eggs.

23:03 These smooth-coated otter pups have spent their first

23:05 6 weeks in the safety of the holt, but now it's time to take to the water.

23:13 And their playground?

23:14 Singapore.

23:15 One of the most densely populated countries on the planet.

23:20 Thanks to conservation efforts such as cleaning up their waterways,

23:24 Singapore now has one of the densest population of otters on Earth, too.

23:30 The otters have made their own.

23:33 And with plenty of fish to hunt, they've even become a tourist attraction.

23:41 The young cubs, still relying on their mother's milk,

23:44 are just learning how to swim.

23:46 And after a successful hunting trip, it's time to try some fish.

23:53 Now, their teeth may be small, but they're still razor sharp.

23:58 In their natural habitat, otters will haul out onto riverbank to feed,

24:03 but in Singapore, this marina works just fine.

24:10 But, house crows have also moved into Singapore.

24:14 Native to India and a few other South Asian countries,

24:18 house crows have hitched a ride on ships all around the world,

24:22 appearing as far away as Ireland, South Africa, and even the USA.

24:27 With big brains and an open mind to all things gastronomic,

24:31 these avian marauders are well equipped for urban life.

24:35 They're a loose social cooperative,

24:38 working together to communicate dangers and to find and share food.

24:44 And why catch food when you can steal it from some youngsters?

24:49 Crows seem to know instinctively that pulling

24:52 tails is a good distraction tactic.

24:58 It almost seems like a game to them.

25:01 They'll even do it when there isn't food involved.

25:06 Show a crow a tail and it seems they'll just pull it.

25:22 And it helps when you have eight other beaks joining in.

25:28 That is until mom's had enough.

25:39 Eventually the cubs do get tired of the hassle.

25:43 Leaving what's left of the fish to the crows.

25:46 Persistence it seems is another key crow quality.

25:52 But the cubs don't seem to mind.

25:54 Plenty more where that came from.

25:57 In just another six weeks they'll be catching fish for themselves.

26:01 But they probably have a lifetime ahead.

26:05 That otter is nosing that fish and sniffing the fish.

26:09 Right?

26:10 And if you look when it first comes up to it puts bubbles out.

26:13 It's got whole loads of bubbles around its mouth.

26:16 Right.

26:17 Well cuz I'm convinced otters can smell underwater.

26:19 So do you think the bubbles are going back into the nose or into the mouth?

26:22 they're going to both.

26:23 Interesting.

26:24 It's not improbable because a lot of animals can smell underwater, right?

26:28 And just a chemical cue and as long as it's

26:31 concentrated so it's like really right close to them.

26:34 Makes sense that they would still be able to smell it underwater.

26:40 So other animals that can smell underwater,

26:42 do they just sniff in water or do they use bubbles in this way?

26:47 You know, to be honest, I don't think anyone knows.

26:52 It's thrilling to think that otter's ability to smell

26:55 underwater could in fact be an undiscovered survival skill.

27:01 I've long thought otters must have this secret ability.

27:05 And seeing this has inspired me to put my theory to the test.

27:17 I'm hoping Rudy might be able to help me once again.

27:23 So really, the only definitive way of proving

27:26 that otters can smell underwater is to do an experiment.

27:29 So what we're going to do is we're going

27:30 to get some fake fish and some real fish.

27:33 And we're going to try and film Rudy telling

27:36 the difference between the fake fish and the real fish.

27:39 So what we got here is a fake piece of plastic trout.

27:45 So we're going to put that on here.

27:49 And we present Rudy with two identical-looking pieces of fish.

27:56 And to see if he can tell the difference.

27:59 So we're going to put this experimental block here underwater.

28:08 This relies on Rudy investigating each piece underwater.

28:13 Deciding which one is food and then eating it.

28:17 And Rod and I capturing the whole thing on camera in slow motion.

28:27 No interest in the fake one.

28:31 Absolutely none.

28:39 Wow, come on Rudy.

28:39 Do it.

28:43 It's so fast and it's so subtle that it's

28:46 very difficult to work out exactly what's going on.

28:50 My camera simply isn't capable of slowing

28:52 it down enough to see the finer details.

28:56 But Rod's camera captures the action 40 times slower than real life.

29:03 All right, Rod.

29:04 Did you get it?

29:05 Yeah, and it's so quick.

29:07 I mean obviously we're slowing it down 40 times,

29:09 so I think until we actually see it Um Oh, well.

29:14 So, that's a white God, that is a close shot.

29:16 That's his head.

29:20 And there's a bubble.

29:21 That's a bubble coming out of his mouth, isn't it?

29:26 Oh, he's sucked it back in.

29:27 He's done it.

29:28 He's done it.

29:29 That was it.

29:30 Fantastic.

29:31 That's amazing.

29:33 A bubble came out of his mouth and just as he was lifting his head,

29:37 he sucked it right back in again.

29:39 It wasn't his nose, but it was his mouth.

29:41 He draws it back in, hopefully tasting the the fish.

29:46 It's amazing cuz you can actually see it happening perfectly.

29:52 Rudy actively pushes a bubble onto the surface of the fish,

29:57 picking up scent molecules before he sucks it back in, obtaining

30:03 enough information to determine whether it's something he wants to eat.

30:09 This footage helps me understand how otters might find food in dark,

30:14 murky waters where they can't rely on their underwater eyesight.

30:19 They sniff it out.

30:21 After being abandoned by their mothers,

30:23 the orphans were brought to Wild Instincts Wildlife Rehab Center.

30:28 On arrival, they were weak, defenseless, and would not have survived the night.

30:36 Attempting to mirror their wild diet,

30:38 center manager Mark is giving them chopped fish and milk formula.

30:47 But he has concerns about the weakest orphan.

30:51 He came to us with kind of a bad leg.

30:53 He had injured the joint on his right rear leg.

30:55 So, we're not quite sure whether it's going

30:57 to heal enough for him to be released or not.

30:59 And he also did a a slight injury to the joint right in here on this leg, also.

31:04 And even the good leg is not necessarily a good leg.

31:07 So, what we're going to do is try to find a zoo

31:09 for him if he's not able to be released back into the wild.

31:13 And if we're unable to find a zoo,

31:15 then he may have to be euthanized if we can't find a place for him to go.

31:21 To keep any attachment to a minimum,

31:24 it's Mark's policy not to name any of the animals in his care.

31:31 Now 8 weeks old, the cubs need

31:34 to tackle an essential survival skill, learning to swim.

31:45 Curiously, baby otters don't really like water.

31:58 So, Mark needs to teach them their most important life lesson,

32:03 that water isn't something to be afraid of.

32:11 Just like their mother would in the wild,

32:13 Mark makes soothing calls to reassure them.

32:20 Each time they try to get out, Mark plops them back in.

32:27 But their swimming lessons don't last too long.

32:34 That's because of another surprising quirk of otter biology.

32:39 Their coat doesn't become waterproof till they're 12 weeks old.

32:44 Until then, being wet could lead to hypothermia.

32:49 So, surrogate mom Mark does what he can to help out.

32:54 Normally in the wild, what they would be doing is rolling around in the grass

32:57 and the dirt to kind of get some of the water off themselves.

33:00 And so, we can use the towels to kind of help us out a little bit.

33:13 Wild otter pups face exactly the same issue.

33:17 So, the adults only take them for short

33:19 dips to stop them getting cold and waterlogged.

33:23 Beautiful.

33:24 The aquarium's head vet, Dr.

33:25 Mike Murray, has anesthetized a female otter for a checkup,

33:30 giving me a chance to take a close look.

33:34 Look at the size of that.

33:36 That's enormous.

33:38 She actually feels really warm.

33:40 Um that really, really thick fur they have is designed to conserve heat.

33:44 And she really doesn't, without the cold water,

33:47 have an opportunity to dump heat.

33:50 Her coat is so effective that Dr.

33:52 Mike has to put bags of ice on her flippers to stop her overheating.

34:00 This is most beautiful, silky-soft fur you can imagine.

34:05 On the outer side, it's much thicker.

34:07 When you get down deep inside, it's just silk smooth.

34:13 You can just make out the sort of pale white skin underneath.

34:19 It's amazing how wet it is on the outside,

34:21 and then you peel it back, and it's completely dry on the inside.

34:26 That's beautiful.

34:28 It's so soft, you can barely feel it.

34:30 It's weird.

34:32 And if you look at the undercoat,

34:34 they've got these long guard hairs, but down deep,

34:37 you look at those microscopically and they've got all

34:39 these little scales that stick off the shaft of the fur.

34:43 And what what the otter does when it grooms is it

34:45 just conditions the fur and get those things to lock together.

34:49 So that it becomes impenetrable to water essentially

34:52 and they can get air in those spaces

34:54 very similar to a down jacket or a down vest that we might be wearing.

35:00 Looking at the undercoat in microscopic detail shows

35:03 these scales lining the shaft of each hair.

35:07 Grooming increases the volume of air trapped in this layer.

35:12 Maximizing its insulation potential.

35:21 And then the freezing waters of Alaska, survival relies on good insulation.

35:29 This mother is fluffing up her baby's coat.

35:33 By blowing into its fur, she's filling it with air to keep him warm.

35:41 The more trapped air, the warmer it is.

35:49 But for it to be effective, it needs to be kept in top condition.

35:55 Which means otters spend hours each day grooming.

36:04 Using their flexible spine to reach those hard-to-get spots.

36:32 Mhm.