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the animal within s02e05
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00:07In the harshest corners of our planet,
00:10where temperatures can skyrocket or plunge below freezing,
00:14life clings to existence in seemingly impossible ways.
00:18These are the extremophiles, nature's ultimate survivors.
00:23Animals who thrive where nothing else can.
00:26These are the unsung heroes of Earth's most extreme environments.
00:31From the soaring heights of incredible peaks
00:34to the frozen deserts of the Arctic,
00:37these remarkable creatures have rewritten the rules of survival.
00:41What's truly remarkable is that these extremophiles
00:44are not just survivors, but they are pioneers.
00:47They're not just adapting to extreme conditions.
00:50They're thriving in them.
00:52How? And what can we learn from their unshakable resilience?
01:18In the vast, frozen expanses of the Arctic, icy winds howl,
01:23and temperatures sink to unimaginable lows.
01:27This is a place where most life simply stops.
01:31A land capable of claiming any ordinary creature within minutes.
01:36So what kind of mammal could possibly survive in this cold wasteland?
01:42Remarkably, one does more than survive.
01:45It thrives.
01:46The polar bear.
01:48A giant predator perfectly suited to rule an empire of ice.
01:53This is really not an animal you want to mess with.
01:56Polar bears are imposing figures.
01:58On their hind legs, they can stand over three meters tall.
02:02That's higher than an NBA regulation basketball hoop.
02:05They can weigh up to 680 kilograms,
02:08making them the largest land carnivore on the planet.
02:12This fierce nature comes as a matter of necessity.
02:16In this barren wilderness, every calorie counts.
02:19And where other bears seek shelter in the winter,
02:22this predator is forced to seek out prey.
02:28Polar bears are apex predators, and they need to eat a lot.
02:31So they'll eat anything they can.
02:35They'll even eat humans if they come close to settlements.
02:41But the majority of its fare will be found on the winter ice.
02:45Polar bears are classified as marine mammals,
02:48the same category as whales or seals.
02:50And this really speaks to how much they depend on sea ice for their survival.
02:54Polar bears are pageophilic mammals.
02:56This means that they depend on sea ice for critical life activities,
03:00such as hunting, mating, feeding, and resting.
03:04To survive on these remote flows,
03:08polar bears require about 12,325 kilojoules per day,
03:13almost one and a half times more calories than an adult human.
03:17And after a summer of scarcity on the shore,
03:20scraping by on kelp and berries,
03:23the bear enters a race against time.
03:25The winter hunt is short,
03:27and it's a challenge best conquered solo.
03:30Polar bears spend their time hunting alone.
03:33If you think about the extreme environment that they live in,
03:35polar bears need to roam around.
03:37So if they're roaming around with other polar bears,
03:39that means they have competition for food.
03:40So being solitary is advantageous for them
03:42because they can take all the food for themselves,
03:44and they can roam further distances.
03:46Movement is key for finding a meal in such sparse terrain,
03:51especially if the bear craves a feast of its favorite fare.
03:55Far from shore, ringed and bearded seals linger near breathing holes
03:59and haul up to rest,
04:02becoming the perfect target for the ravenous polar bear.
04:06A single adult bearded seal can contain up to 180 kilograms of blubber.
04:11A polar bear can consume up to 45 kilograms of blubber in one sitting.
04:15That's more than a million kilojoules of energy.
04:18They need that energy to travel the distances that they do.
04:21Seals, however, are agile swimmers that can easily avoid ambush.
04:26To stealthily track these animals down,
04:29the polar bear deploys its superb olfactory talents.
04:33Polar bears can smell seals up to 32 kilometers away,
04:37even through thick ice.
04:39This is like smelling a hamburger in the next town over.
04:42In their big snout, they have a very large,
04:46what's called an olfactory mucosa,
04:48which is covered in sensory receptors.
04:50When those sensory receptors detect stimuli,
04:54then it transmits that information up to the olfactory bulb,
04:58which is kind of like the processing center in the brain
05:00that interprets all that information from its sensory receptors.
05:04But once the polar bear catches a scent,
05:07how does this giant mammal,
05:09weighing hundreds of kilograms,
05:11silently sneak across the ice without making a crack?
05:14The answer lies in its massive paws,
05:18often measuring 30 centimeters in diameter,
05:21which act like natural snowshoes distributing its weight across the fragile ice.
05:27Added to this engineering are a layer of small traction-aiding bumps known as papillae.
05:33All bears have papillae on their paws.
05:36But what makes the papillae of polar bears so special is that they're much longer.
05:41So it's kind of like snow cleats that grip the snow.
05:44They can get lots of traction in those snowy and icy surfaces.
05:48Scientists and engineers look to nature to improve products.
05:53Polar bears have a great traction system.
05:56Designs for hiking boots, for snow tires, for high-altitude climbing equipment,
06:02are starting to include papillae like those from the polar bear's feet to improve traction.
06:09Traction is just one element of the hunt.
06:12As the polar bear hones in on its prey,
06:14these paws transform into deadly weapons.
06:18The polar bear stalks quietly,
06:20so it waits patiently near the breathing hole of a seal.
06:23And as soon as a seal emerges,
06:26it strikes quickly, powerfully,
06:28pulls the seal out of the water with its massive claws.
06:33Polar bears have an impressively strong bite force,
06:36the strongest of any bear.
06:38It can tear through muscle, break bones.
06:40That's really effective for tearing through the tough hides of its seal prey.
06:47The hunt is a success.
06:50In the deceptive calm that follows,
06:52polar bears enter the vulnerable period of digestion.
06:56Taking a nap on the ice,
06:58their massive body is seemingly at rest,
07:01but it wages an invisible war.
07:03Because even in the warmth of the sun's rays,
07:05temperatures here can reach as low as minus 50 degrees Celsius.
07:11Luckily, evolution has armed these giants with a secret weapon,
07:15an extraordinary thermoregulation system,
07:18at the core of which is their fur.
07:22Polar bears have a couple of different types of fur.
07:24The base layer that's closest to the skin is really insulative.
07:29It's downy and it absorbs a lot of heat.
07:32On top of that downy layer are guard hairs, longer hairs.
07:36These hairs are somewhat translucent.
07:38When we look at them from afar, they're white,
07:41but if you look at them up close, they're actually somewhat clear.
07:44They're actually arranged in such a way that when the animal loses heat from its body,
07:49it actually helps reflect that heat back towards the surface,
07:52so that it can be reabsorbed by the skin.
07:56But fur alone won't do the trick.
07:58Beneath this, the polar bear has another hidden advantage.
08:03Polar bears are classically known for their white fur,
08:05but what's very interesting is that the skin under the fur is black.
08:09And you can see the black skin if you look at the snout,
08:12you'll see that it's black around the nose.
08:13And that black colour is then really effective for reabsorbing the heat
08:18that might be reflected back from those inner layers of the fur.
08:21This insulation system is critical if the bear is to survive.
08:26When the hunt calls, this mighty mammal must answer,
08:29even if it means plunging into the waters that hover near freezing.
08:34In fact, scientists have recorded these animals swimming up to 687 kilometres
08:40over the span of nine days at a time.
08:42And on such an aquatic voyage, these robust layers of protection
08:47mean the difference between life and death.
08:50Their fur has to not only provide a lot of insulation,
08:54it also has to protect against water infiltration into the undercoats
08:59into the polar bear's skin where it would cause them to get cold very quickly.
09:03So the polar bear's fur is not only highly insulating,
09:07but also repels water.
09:11Taking a cue from the polar bear, researchers are studying how the fur traps heat
09:17and minimizes heat loss, with the goal of replicating these properties
09:21to create more efficient clothing and insulation for humans.
09:25Researchers at the University of Massachusetts have successfully created
09:30a synthetic version of polar bear fur.
09:32So the fabric is a two-layered fabric that mimics the long shafts of the polar bear guard hairs
09:39and its black skin.
09:41What that allows is for it to be much thinner than traditional fabrics,
09:45and it's really good at retaining heat.
09:48On even grander scales, polar bear fur has also inspired sustainable building design.
09:53Researchers have created a carbon tube that emulates the structure of polar bear hair.
09:59It's very lightweight, it's very flexible, and it can also repel water in much the same way,
10:04so it's great for building materials.
10:08Despite possessing a cutting-edge coat,
10:11slipping into waters comes with a crude calculus for the polar bear,
10:16one that involves its very survival.
10:20Swimming is an incredibly energy-intensive activity.
10:24Polar bears burn up to three to five times more energy swimming
10:27than walking an equivalent distance.
10:29So what happens when they're weakened by hunger?
10:33When a polar bear hasn't fed in weeks, is the energy cost worth the gamble?
10:38It has to decide whether the reward of a potential meal
10:41is worth the risk of exhaustion in the open water.
10:44Many polar bears can go up to 130 days without eating.
10:48When they don't eat, polar bears can lose up to a kilogram of mass per day.
10:52It's really feast or famine for these creatures.
10:56To help the polar bears survive periods of scarcity
10:59and provide additional insulation against the Arctic chill,
11:03the polar bear relies on a crucial fat reserve.
11:07Polar bears have a very thick layer of fat under their skin.
11:11It can be over 11 centimeters in thickness.
11:14And that's really important for insulating them, especially in the water.
11:17Because in the water, when the fur gets wet,
11:20that reduces its insulative properties.
11:22But the fat can always act as an effective barrier against losing body heat.
11:27It also operates as an important energy reserve
11:30when they go long periods without eating.
11:34This layer of fat fluctuates from season to season.
11:39As spring arrives and the ice retreats,
11:42polar bears face a long exodus to land where food prospects are more bleak.
11:51For a female, this fat reserve becomes the thin line between life and death.
11:58The winter months bring her darkest trial,
12:01birthing and nursing cubs while unable to hunt.
12:05During this time, she may go up to eight months without eating,
12:09relying entirely on her fat stores for energy.
12:12So how does her body adapt to such an abrupt change?
12:17It's really important during these periods that they not waste energy.
12:21They conserve every bit of energy that they have.
12:23So what they do is they enter a kind of light hibernation
12:27where they depress their metabolic demands,
12:29they lower their heart rate,
12:30and they reduce the amount of energy they need to survive.
12:35This is an animal remarkably forged by millennia of ice and snow,
12:40equipped to handle even the harshest of terrains.
12:43Yet, for all its evolutionary skill,
12:46there exists one catastrophic hurdle that renders this predator near defenseless.
13:03The polar bear is a symbol of climate change.
13:06Their entire lifestyle revolves around sea ice.
13:09Already due to climate change,
13:11sea ice has been covering less and less of the ocean.
13:13For less and less time of the year.
13:15With a lack of sea ice,
13:16one of the most dangerous things for polar bears is they can't rest.
13:19So if they're swimming for long periods of time,
13:21they can actually run out of energy and just drown.
13:23What's happening now is they actually tend to not go out at sea
13:26because there's not enough sea ice.
13:28They don't want to drown.
13:29So they'll actually stay on land and eat small critters.
13:32It's just not helping them in terms of the amount of energy
13:34that they need compared to seals.
13:3740 years ago, polar bears typically spend a few weeks on shore.
13:42Today, they spend approximately two months on land.
13:46Because polar bears are spending more time on land,
13:49there's more chances for interactions with humans,
13:51which is not good for the bear or the humans.
13:54Today, the polar bear is on the front lines of climate change
13:58as one of the most affected animals by the Arctic melt.
14:02Yet, even in the face of this harrowing change,
14:05the polar bear remains a creature of remarkable resilience,
14:09expanding its diet and territory, altering its hunting strategies,
14:14and carrying the fierce determination to endure,
14:17even when the odds are stacked against it.
14:25Further south, another, much tinier animal,
14:29has its own toolkit to contend with drastic shifts in the environment.
14:33Here in North America's boreal forest,
14:36a vast and enchanting wilderness stretching over 1.5 billion acres,
14:42across both shores from Newfoundland to Alaska,
14:45the winter chill can drop to minus 50 degrees Celsius.
14:49Amid these frigid dips,
14:52a remarkable survival story unfolds.
14:58The wood frog is a small amphibian with an extraordinary ability
15:02that defies nature's harshest conditions.
15:07Wood frogs are the amphibian that lives farthest north in the world.
15:11And to do this, they have the really unusual adaptation
15:15of being able to essentially freeze and come back to life.
15:20This is like science fiction-level stuff happening at the level of a little frog.
15:26The life of the wood frog begins in an amphitheater of sound,
15:30where adults gather and croak for breeding season in early spring.
15:37All frogs have a distinctive call.
15:39And the wood frog sounds like ducks quacking.
15:46Once the females find a mate, then they lay their eggs in shallow bodies of water,
15:51and then the males come and fertilize them.
15:54The eggs hatch in about a week, and the tadpoles grow quickly in the warming water in the spring.
16:00And that breeding season occurs over a relatively short period of time
16:04before these shallow pools that the tadpoles develop in can dry up.
16:09But once they make their way to land, danger awaits.
16:13In spring, summer, and fall, wood frogs spends a lot of time dodging predators.
16:18Other larger frogs, snakes, birds, and other mammals.
16:22As winter approaches, wood frogs prepare to meet another deadly foe,
16:26the bracing cold temperatures of the winter.
16:29The winter shows no mercy.
16:32For a cold-blooded creature, there is no escape from this assassin.
16:36The Arctic air threatens to turn water to ice and slow the frog's blood to a crawl.
16:42Many cold-blooded creatures will exhibit what's called brumation,
16:46where they depress their metabolism to save energy.
16:50Brumation keeps cold-blooded creatures like snakes, turtles, lizards, frogs, and salamanders, semi-alert.
16:59They still wake up occasionally, maybe to drink, to urinate,
17:02or even take a bite if conditions allow.
17:06However, the wood frog takes a more extreme approach to survival.
17:10Instead of brumating and waiting for winter to pass, it becomes winter.
17:16The wood frog undergoes a major transition like no other.
17:19Its heart slows down and stops, its muscles stop moving and stiffen, and it freezes solid.
17:26They shouldn't survive.
17:28But most creatures facing a freeze would also face imminent death.
17:34Although the wood frog will freeze solid, the difference lies at the cellular level.
17:40Normally, when an animal freezes, the water inside their bodies become shards of ice,
17:46which would destroy the cells and eventually kill the animal.
17:51Ice occupies a volume about 9% larger than liquid water.
17:56When a cell freezes and you get that 9% volume expansion, the cell bursts.
18:02To avoid this explosive fate, the wood frog has developed unique adaptations
18:07to become the Sub-Zero Exception, biologically manufacturing its own antifreeze system.
18:14They have an ice nucleating protein that's enriched in their plasma and extracellular fluids.
18:22What that does is it makes the animals freeze around their cells, but not inside their cells.
18:29By freezing the environment around the cells, the cells themselves can actually stay intact and stay alive.
18:36Within the cells, the wood frog also possesses another chemical secret,
18:41a cryoprotectant in the form of glycerol.
18:46Glycerol is a compound much like the antifreeze in cars.
18:51Antifreeze in cars is glycol, quite a similar compound,
18:56that also depresses the freezing point so that the fluid in our radiators don't freeze.
19:01So frogs have developed a system that's very analogous to what we use in cars
19:06to prevent the liquid in their cells from freezing.
19:10Although the cells are now protected, freezing causes its heartbeat and vital functions to slow.
19:17How do its organs survive without oxygen?
19:21As the wood frog's heartbeat and breathing stops, it switches modes from aerobic respiration,
19:26which involves the lungs and the heart, to anaerobic respiration, which only involves glucose.
19:32In the days and hours before freezing, the liver excretes a huge amount of glucose,
19:37one last big dose to sustain the frog's cells and tissues through the winter.
19:42Powered by this glucose alone, the wood frog can remain in a frozen state for up to seven months.
19:48Hidden away under leaves and brush, they go undetected by heat-seeking predators.
19:54But as the harsh winter retreats, the world begins to warm,
19:59and the wood frog starts their next miraculous transformation, the thaw.
20:06When the wood frogs then thaw, all the ice in their extracellular fluids is being converted into dilute water.
20:14And this presents a problem, because as dilute water then surrounds their cells,
20:19that water will rush inside the cells and cause them to burst.
20:23Once again, glucose steps in to manage the process, acting as a cushion to control how water flows into the
20:30cells.
20:30The glucose keeps the water from rushing into the cells and causing those cells to burst.
20:37As they're coming out of the frozen state, their metabolism is increasing.
20:40And so having this glucose to actually kick-start their metabolism and get things going is really important.
20:49The wood frog's remarkable ability to freeze and thaw without damage
20:54captivates researchers seeking to improve organ preservation for transplantation.
21:00Today, there remains a pressing need for transplantable organs.
21:05One of the problems with transplanting organs between a donor and a recipient is,
21:11we really have to make sure that we do it quickly, because otherwise the organ will die.
21:16We can't freeze organs right now, because if we do that, the cells will burst and will die.
21:21Inspired by the wood frog's use of glucose, scientists are testing sugar-related compounds to help protect human cell damage
21:29caused by freezing.
21:31In one study, sugars help keep rat livers alive for up to 96 hours in a frozen state.
21:40Scientists are also investigating the wood frog's secrets to revolutionize human-made materials.
21:45By mimicking the frog's natural capabilities, researchers have created an anti-ice coating,
21:52with potential for use in aerospace engineering on roadways and runways.
21:57The idea is to have a surface that is, in and of itself, ice-phobic, something that we don't need
22:03to regularly apply anti-freeze to.
22:06This coating could be used on everything from plane wings to space capsules, from bridges to roadways,
22:12and anywhere else where we wouldn't want to have ice formation.
22:16Though humanity has far to go in trying to match the wood frog's ability to survive and thrive in below
22:22freezing temperatures,
22:24its subtle anti-freeze mechanisms provide much inspiration for those working on the cusp of great discovery.
22:33A world away, high above the forest floor, another hardy creature has garnered human interest for millennia.
22:41From the Himalayan mountains to the Tibetan plateau, it has conquered Earth's most extreme altitudes,
22:49creating life at elevations of over 6,000 meters.
22:53Above the clouds, in the treeless tundra, lives the planet's highest-dwelling mammal, the yak.
23:01Yaks live in a topography that is quite treacherous.
23:04There are mountains, highlands, large lakes, and rugged interior.
23:09It is covered in an extensive permafrost that gets drier as the altitude increases.
23:16Receiving only between 100 and 300 millimeters of rain, it is a polar desert.
23:21In these arid conditions, adaptability is key, and survival demands numbers.
23:29It is a social animal, living in herds formed by mostly female yaks and their young.
23:34Group sizes can range from 10 to 200 individuals.
23:37For most of the year, these high societies remain calm, collected, and cooperative.
23:43But once every year, the gentle giants transform into fierce gladiators,
23:49as bulls engage in head-to-head battles for breeding rights.
23:53The traditional mating season of yak runs from July to September.
23:58And during this time, males engage in intense competition for females.
24:03In this battle, only the strongest bulls will earn the right to secure their lineage.
24:09These titans of the high peaks are built for battle, with a shoulder height that can reach up to 205
24:16centimeters and sharp horns that can grow nearly a meter long each.
24:21Weighing up to 1,200 kilograms, about the size of a small car, yaks are a force to be reckoned
24:28with.
24:28But how does such a massive mammal contend with its greatest threat of all?
24:34Not other yaks, or even hungry predators, but a silent killer invisible to the naked eye.
24:41The air itself.
24:45One of the most significant challenges at high elevation is the low level of oxygen in the air.
24:51And the big problem with that is that it threatens reducing the amount of oxygen in the tissues.
24:56And that's what we call hypoxia.
24:59Hypoxia is something that's extremely damaging that can reduce an animal's metabolism and even threaten its life.
25:06When an animal gets hypoxic, it can start to experience labored breathing and its skin can even get a little
25:12bit blue, which is a sign of lack of oxygen in that area.
25:16At altitudes where the yak lives and grazes, the thin air has 40% less oxygen than at sea level.
25:23An oxygen desert that could suffocate the average mammal.
25:27So how does this bovine creature beat the odds?
25:31First, it harnesses oxygen in a way that other animals simply cannot.
25:37Blood is really important to transporting oxygen throughout the body.
25:41And within the blood are red blood cells that contain hemoglobin.
25:45Hemoglobin is a vital protein in this process because it binds oxygen and carries it throughout the body and then
25:53releases it to those cells that need it.
25:55When most animals move to high altitudes, their bodies produce more red blood cells.
26:00More red blood cells means more hemoglobin means that when you breathe air, more of the oxygen makes it into
26:07the blood.
26:08This sounds like a really great thing, but it comes with a major drawback.
26:13As more red blood cells infiltrate the body, the blood itself becomes thick and sluggish, stuck in a circulatory traffic
26:21jam.
26:21That can contribute to blood clots, and it's also one of the main causes of chronic mountain sickness, a really
26:28debilitating condition that occurs in many human populations throughout the world.
26:33So how does the yak contend with a potentially thick overflow of hemoglobin?
26:38Yaks actually have a type of hemoglobin that absorbs and releases oxygen more readily.
26:46This way they don't need to have more red blood cells to transport the same amount of oxygen.
26:53To face the rigors of the low oxygen environment, the yak is also outfitted with a biological engine in the
27:00form of an extra large heart.
27:01The heart of a yak is more than twice the mass of the heart of cattle from sea level.
27:07A huge heart means that they can move blood through their system very quickly.
27:12The faster the blood moves from the lungs to the muscles, the more effectively they can use the oxygen.
27:18And this heart doesn't work alone. Working in tandem are its oversized lungs.
27:25When paired together, they crack the code that stumps most other life forms.
27:30How to extract maximum oxygen from air so thin it barely qualifies as breathable.
27:36To make space for these supersized organs, evolution has engineered the yak with an extra large thorax.
27:42They actually have an extra set of ribs compared to cattle.
27:45The thorax plays a really important role in breathing that expands and inflates the lungs every time these animals breathe.
27:55With such a sophisticated furnace to power life at extreme altitudes,
28:00the yak must also ensure it keeps these internal mechanisms safe against the merciless cold.
28:07The Tibetan Plateau can get as cold as minus 40 degrees Celsius in the winter.
28:12And this presents a really significant challenge to animals.
28:16They need to maintain their body temperature and avoid losing their body heat to that really cold external environment.
28:24Luckily, the yak wears a luscious coat of fur that does just this.
28:29It has an outer coat of long fur with a downy layer underneath that's really effective at insulating the animals
28:37from the cold.
28:38Yet at such high altitudes, the cold air isn't all the yak has to worry about.
28:44Up here, it must also contend with the extremes of heavy, wet snow and the unrelenting radiation of the scorching
28:51sun.
28:52Yak hair can absorb up to 35% of its weight in water and still stay dry to the touch
28:58and still maintain its insulative properties.
29:02Because yaks live at extreme altitudes, their fur has evolved to be highly resistant to UV radiation.
29:09And for this reason, the yak's fur makes very durable rope.
29:14When you leave it out in the sun, the UV rays tend to break down the polymer, break down the
29:19fibers and make the rope weak.
29:21Because yak fur has this inherent UV protection, it's very durable and lasts a long time.
29:27On this mountainous terrain, the rules of survival change at every elevation.
29:34In their lifetimes, yaks will make the endless vertical journeys in their quest for food.
29:39Trekking from around 3600 meters to over 6000 in search of the perfect sweet spot.
29:46During colder months, yak migrate to lower plains and primarily eat grass.
29:51As the temperatures warm, then they'll return to higher elevations and eat moss and lichen, scraping it off the rocks
29:58with their tongues.
30:00This steep terrain doesn't make for an easy trek.
30:03One slip could spell certain death.
30:06Luckily, these massive mammals are surprisingly nimble.
30:11They can swim across river rapids, plod across squishy marshes and can even clear pathways through snow.
30:19Their nimbleness is also key to evading predators like the Tibetan wolf and the snow leopard.
30:26They're able to retreat to higher elevations where their predators simply can't cope with the low levels of oxygen.
30:34For a speedy escape, the yaks rely on their well-designed hooves, each equipped with a supportive and shock absorbing
30:41suspensory apparatus.
30:44As the yak's weight is distributed across its body, the suspensory ligament stretches, absorbs the weight and helps transmit power
30:52during movement.
30:53Their hooves are also cloven, increasing their balance on treacherous terrain.
30:59Cloven means the hoof is essentially split into two halves, like the yak has two toes.
31:04This is really effective because it means it has two surfaces for spreading out and supporting the weight of the
31:11animal.
31:12On either side of the hoof are two small dew claws that help provide some extra grip and stability.
31:18And how do they combat the discomforts of traversing both frozen tundra and scorching mountain rock?
31:27Specialized podiatric fat pads that also act as nature's ultimate shock absorbers.
31:34With every step the yak takes, these fat pads absorb vibrations.
31:39They essentially act like an airplane shock absorber called an oleostrut.
31:44The yak's natural shock absorbing foot pad also act as insulation against frostbite.
31:51Without this protection from the year-round frost in the Himalayas, the bottom of the yak's feet would freeze.
31:58The yak's hardy hooves have inspired incredible advancements in the world of robotics.
32:05Chinese scientists have looked to the yak's foot for inspiration when it comes to building robots.
32:12With legged robots, it's really difficult to maintain stability.
32:17By using mechanisms like those that are present in the yak's foot, we can increase the stability of robots, making
32:24them more capable.
32:26After navigating treacherous peaks, the yak finally reaches its grazing destination.
32:32Here, it has a brief window of opportunity to feed, and every moment counts.
32:38Wolfine tongues are covered in papillae.
32:41They're little bumps that help grip the food inside the mouth.
32:45And what's unique about yak tongues is that they have larger papillae that have keratin in them.
32:51And this is really effective for grinding the food against the roof of the mouth.
32:55For a yak at high elevation, food is scarce, and so they really have to take what they can get.
33:00For example, plant stems or wilted leaves.
33:03To compensate for this meager variety, yak's papillae actually have fewer taste buds.
33:09This is actually quite helpful in environments where beggars can't be choosers.
33:14Once the tongue moves their food to the back of their mouth, it's transported into the yak's four-chambered stomach.
33:21In addition to being unappetizing, some of the plants consumed by the yak at high altitudes are difficult to digest.
33:29This four-chamber structure allows food to digest longer in the stomach so that yaks can absorb more of the
33:37nutrients in the plants that they eat.
33:38To supercharge the yaks' ability to glean nutrients from the sparse vegetation, the yak's stomachs contain distinctive bacteria and fungi
33:47helpers,
33:48allowing them to digest tough fibers like cellulose that cows would have difficulty digesting.
33:54Without this optimization, yaks couldn't survive in their native environment.
33:59So impressed by their remarkable adaptations, humans began domesticating these bovids over 7,000 years ago,
34:07as a source of wool, milk, and most importantly, guidance through the Rocky Mountain steppes,
34:14forging a connection to the animal kingdom that has endured for millennia.
34:19Compared to their bovine cousins, yaks have been upgraded by nature to have many features that allow them to cope
34:26with the challenging environments in the mountains.
34:31While the robust yak is the ultimate survivor in cold, high-altitude environments,
34:36a tiny creature defies the harsh desert landscapes of North Africa and the Arabian Peninsula.
34:44In the driest places on Earth, where the sun is relentless and the wind whips over endless dunes,
34:51survival demands innovation.
34:55One desert dweller has mastered the art of resilience,
34:58with a body built for speed and a metabolism designed to conserve every precious drop of water.
35:05This is the Jeboa.
35:10The Jeboa is a small nocturnal rodent that lives in the deserts and steppes of Asia, North Africa, and Eastern
35:18Europe.
35:19Dozens of species exist, from the Sahara to the Gobi, each masterfully suited to thrive in their volatile desert terrain.
35:28By day, the Jeboa faces the unforgiving heat, often reaching 55 degrees Celsius at its hottest.
35:36By night, it endures freezing cold, with temperatures plummeting as low as minus 5 degrees Celsius.
35:45Yet, despite these extreme fluctuations, this creature prevails.
35:50It's a solitary creature that forages at night for insects, roots, seeds, and plants, and spends the rest of its
35:57time hiding in underground burrows.
35:59They're quite small, only reaching about 15 centimeters in length, and they weigh about the same amount as a couple
36:05of coins, so 23 to 37 grams.
36:09These tiny creatures are extremely fast. They can reach speeds up to 25 kilometers per hour.
36:16They hop on their hind legs, looking a little bit like teensy kangaroos.
36:20And when they're standing still, they rest on their tail.
36:23The Jeboa uses its speed and superior night vision to dodge predators like owls, snakes, cats, and foxes.
36:32How does it do it?
36:34Their oversized eyes allow them to detect movement and see more clearly during twilight nocturnal hours.
36:41These are the times when the Jeboa is the most active.
36:46Every hop is a calculated risk for this tiny creature, as dangers from predators abound.
36:53The Jeboa's strong hind legs are actually built for incredible jumping.
36:57All the bones in its foot are actually fused into what's called a cannonball.
37:01It's great for leaping long distances, and its feet are actually covered in little hairs that keep it from sinking
37:08in the sand.
37:08And when they're threatened by predators, Jeboas use a unique evasive technique characterized by sudden changes in direction, gait, and
37:18speed.
37:23The Jeboa's movement is kind of like a cross between a rabbit and a kangaroo.
37:29They have very large, powerful hind legs that allow them to leap long distances, and yet they've retained the ability
37:37to turn almost instantaneously like a rabbit does.
37:40By incorporating these random movements and acrobatic leaps into their escape strategy, Jeboas are able to confuse predators,
37:49which significantly increases their chance of survival in the open desert landscape.
37:54But to survive against a bevy of predators is one thing.
37:58Surviving the environment itself is something else entirely.
38:04The Jeboa has very large ears with a lot of tiny capillaries in it.
38:09This allows the Jeboa to circulate a huge amount of blood through the ears, cooling that blood to keep the
38:17animal cool enough in the high temperature desert environment.
38:21Keeping cool is one hurdle.
38:23Now comes the challenge of staying hydrated in a habitat where water is extremely scarce.
38:29In desert environments, animals really have to be very conscious of water management.
38:35Jeboas don't have access to fresh water.
38:38They get all of their water from the plants that they eat.
38:41So keeping that water and retaining it is really important.
38:44The Jeboa doesn't sweat, so it doesn't lose water that way.
38:48So the only really other significant loss of water is through urine.
38:52The kidney's primary function is to remove urea from the body.
38:57Urea is a very strong compound.
39:00And if you concentrate it too heavily, it can cause damage.
39:05It can reabsorb back into the body.
39:08And it's very difficult to excrete large amounts of urea without excreting water.
39:15The Jeboas kidneys have developed the ability to excrete very concentrated urea solutions.
39:21This means that the Jeboa is conserving water because it's not eliminating it with its urine.
39:29When moisture from food sources dries up, Jeboas resort to a critical survival skill, digging.
39:37The Jeboa is optimized for digging.
39:39They have short, powerful forearms with sharp claws that dig the sand, and they have long, powerful legs that kick
39:45the sand out of the burrow.
39:46They dig for water, and they dig burrows to hide from predators and the extreme heat.
39:51Like a rigorous architect, the Jeboa constructs several types of burrows, each perfectly designed for its own unique purpose.
40:00The Jeboas use temporary summer burrows while they're foraging.
40:04These are relatively simple and just provide them with some cover from the elements.
40:08They also have permanent burrows that are much more complex and have many different chambers in them for doing things
40:15like storing food.
40:16These permanent burrows are also cleverly lined with emergency tunnels, allowing for a quick escape from predators.
40:25This becomes especially vital when the Jeboa has something irreplaceable to protect.
40:30Its young.
40:32The mother spends 30 to 45 days underground with their young.
40:37Their young are helpless and they're really susceptible to predators, so the mother protects them in their burrows during this
40:43time.
40:44For adult Jeboas, permanent burrows also become a hideaway during periods of extreme heat, when their bodies go into a
40:52form of deep rest called estivation.
40:55Estivation is a form of dormancy, similar to hibernation, but during hot and dry conditions.
41:09When they're dormant, their metabolism slows down and they conserve energy and water until temperatures cool off a bit.
41:17When temperatures drop, Jeboas use these same burrows for hibernation.
41:22In the frigid Gobi Desert, where temperatures can drop to minus 40 degrees Celsius in winter, Jeboas sleep for up
41:31to five months.
41:32But it's not just the Jeboas' long reprieves and water conservation efforts that make it a finely tuned survival machine.
41:41Recent research has shown this small desert creature has evolved the remarkable ability to repair its own DNA.
41:50What's been found is that high elevation Jeboas actually have mutations in specific genes.
41:56The ATR gene activates a special protein that essentially acts as a sensor for DNA damage.
42:03And what that means is that when high UV radiation causes damage to their DNA, they're much better at repairing
42:09it.
42:10This adaptation is especially beneficial to Jeboas dwelling in high altitude desert habitats, like those in northern China, where the
42:19atmosphere thins and offers little protection against the sun's harmful UV rays.
42:25Without this evolutionary defense, DNA damage would trigger mutations that could otherwise lead to severe health problems.
42:35These insights we've gained from Jeboa might be really useful for stimulating future research to understand how we can overcome
42:43UV-related skin conditions.
42:46The Jeboas' water-conserving kidneys could also provide much fodder for future research.
42:51Water purification and conservation is really important in water-scarce regions and even during prolonged space flight.
43:00So the more we can learn about means of water purification, even in places like the kidneys and the exceptional
43:08kidneys of the Jeboa, this might help inspire future technologies.
43:12The Jeboa flourishes where few others can, adapting to extreme heat and scarcity with unmatched precision.
43:23So what happens when nature flips the script? Halfway around the world, in Japan's snow-covered mountains, another survivor battles
43:32the opposite extremes.
43:35In the Chubu region, water doesn't disappear, but transforms into icy vistas.
43:41Here, winter temperatures can plunge to minus 10 degrees Celsius, and blizzards rage for months.
43:49While most creatures flee this frigid terrain, preferring the comfortable deep sleep of hibernation, one is intent on sticking it
43:58out.
43:59The Japanese macaque, a creature of remarkable intelligence, adaptability, and striking contrasts.
44:08The Japanese macaque is affectionately known as a snow monkey, and it's a resilient primate that's known for its adaptability
44:16to harsh environments.
44:18They don't move around a ton and typically live in an area of about four square kilometers, but this can
44:23change a lot depending on the season.
44:26Waging a war against winter's wrath takes remarkable stamina.
44:31And although in captivity, Japanese macaques can live almost 30 years, in the harsh wilds of Japan, their lifespan is
44:39typically more like six years.
44:42Surviving even that long requires the power of community.
44:48In the wild, Japanese macaques live in highly social groups.
44:53Typically, these are matrilineal groups and females inherit their ranks from their mothers.
44:58Higher ranking individuals, particularly females, have priority access to food resources, especially during times of scarcity.
45:06This system ensures that at least some members of the group are able to maintain good health and successfully reproduce,
45:13even in challenging conditions.
45:15And how do they maintain these strong social bonds?
45:19Like a day at the spa, it's mainly through communal pampering.
45:24This activity not only keeps them clean, but it also improves social bonds within the group.
45:32Japanese macaques are master foragers, dining on leaves, insects and fruits.
45:37During the spring, summer and fall, tree climbing provides macaques with resources not available to ground-dwelling creatures.
45:46And up here is the perfect vantage point to spot danger.
45:53Japanese macaques have traits ideal for climbing trees.
45:57Their opposable thumbs allow them to grip branches firmly, and their strong, flexible limbs allow them to climb trees more
46:03easily.
46:06Jumping from branch to branch is not all fun and games for the snow monkey.
46:10After first snowfall, food becomes scarce.
46:14The ground will remain blanketed for at least three months.
46:18As temperatures drop precariously, it is time for the Japanese macaque to close ranks and get creative.
46:26In the harsh winters or times of scarcity, these social animals will work together to help each other out.
46:33They huddle together for warmth, and they help each other find food.
46:37The Japanese macaques have developed the ability to fish, which is a fairly new strategy.
46:42They'll turn over rocks to catch the fish, and they'll also stand up and just go and grab the fish.
46:47They'll use rocks to open up tough foods, and they'll even dip it into the hot springs to soften it,
46:51just like a fondue.
46:52Yet, the fat stalls from a full belly of fish won't be enough to keep this primate warm.
46:59Fortunately, the macaque also dons a luxurious coat of fur, a natural barrier between its body and the biting cold
47:07winds.
47:09The secret to the coat's warmth lies in its intricate structure.
47:12It has multiple layers, and the layer closest to the skin is a very insulative, downy layer that helps keep
47:20the body warm when the environment around the animal is really cold.
47:24This cozy coat grows as temperatures plummet, and is cleverly fitted to the most ideal area of the monkey's body.
47:31So the fur is not uniform across the body.
47:35Its face and its rump are actually exposed and not covered with fur.
47:39And this is really useful for regulating the animal's body temperature.
47:44When temperatures go up, they can actually send more blood to the skin in these regions, and get rid of
47:50heat to the environment to help themselves cool.
47:53But when the temperature drops, they can take the blood flow away from those skin regions, and actually conserve heat
48:00to the core tissues, and avoid losing too much heat to the environment.
48:04The macaque's winter get-up isn't just for warm.
48:07It's a surprising acid for an unexpected winter pastime.
48:12Swimming.
48:15If you don't have good adaptations, your fur is going to get wet, absorb water, and you're going to get
48:21cold.
48:22The macaques have produced an adaptation that prevents their fur from getting wet, so that they don't get that cold
48:29associated with wet fur.
48:31With their fur grown out and their bodies protected, these monkeys are now safe to shift into low gear.
48:38In the winter months, Japanese macaque reduce their overall levels of activity.
48:43They're most active around noon in the middle of the day when they go out to forage, and then they
48:48sleep overnight.
48:49But what's interesting is this is totally different from what they do in the other seasons of the year,
48:54when they're actually much more active overnight, and they sleep during the day.
49:00Yet, even this calm winter state requires a jolt of energy every now and again to catch prey, move about,
49:08and most importantly, to keep warm.
49:11So the big challenge that a Japanese macaque faces in the winter is keeping its body warm.
49:17And so when it experiences cold in the winter, it increases its metabolism to generate body heat.
49:23And one of the ways that they do that is they produce and release a hormone called cortisol.
49:30Cortisol is released by a gland called the adrenal gland, which is just above the kidneys, and it circulates throughout
49:37the body,
49:38and it tells all the cells in the body to take up more carbohydrates from the circulation and increase their
49:44metabolism.
49:45And that's one of the ways in which they stimulate those cells to generate more body heat.
49:51When a thick fur coat and a hormonal kickstart aren't enough to keep warm,
49:56the Japanese macaque resorts to the earth itself, seeking out nature's own hot tubs in the middle of the mountain
50:03terrain.
50:04Here they gather in natural hot springs, where the steaming water provide the perfect escape from the harsh cold.
50:13Japanese macaques are not only tough, but they're resourceful.
50:16This is a rare display of behavioral adaptation to an environmental challenge.
50:21The Japanese macaque holds a unique and relaxing position in the animal kingdom as the only primate known to soak
50:28in natural hot springs.
50:29According to local tales, it all began when a young macaque entered an outdoor hot spring near Jigokudani Monkey Park,
50:37and her peers soon followed suit, turning a daring plunge into a winter ritual that has since shielded the truth
50:45from frostbite and hypothermia.
50:48Interestingly enough, when the macaques are lounging in the hot springs, they also have lower cortisol levels.
50:56And this makes a lot of sense because they don't have to generate as much body heat because the hot
51:01springs are doing it for them.
51:02And so that reduces their energy costs, it reduces their cortisol levels, and that's really advantageous because that means they
51:10don't have to forage as much and they can save their energy.
51:13The Japanese macaque's remarkable cold weather adaptations, physiological and behavioral, may hold valuable lessons for our own survival in a
51:24world of extremes.
51:26The lessons of the animal kingdom are not just a study in survival, they are a blueprint for thriving in
51:33nature's harshest conditions.
51:59But we really appreciate that.
52:00And then we'll see you soon.
52:00We'll see you soon.
52:01Bye.
52:07Bye.
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