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00:00The human species has long admired strength and power.
00:04We think we have a lot of strength, but we're really not the strong men.
00:07While we search for new ways to push beyond our own physical capabilities,
00:11the animal kingdom has evolved their bodies to achieve incredible things that humans simply can't.
00:17That would be like picking up a couple of SUVs under each arm.
00:21It's an ancient set of tools and tricks from a biological perspective.
00:24A crushing bite or an impervious hide can give an animal a competitive edge.
00:29It's got to be quick. It's got to be ready to fight.
00:32It's all about breeding and eating. It's critical for their survival.
00:35What can we learn from these animals' engineering?
00:37We are trying to achieve what biology has perfected.
01:02What if a human could lift six double-decker buses or be born with a built-in suit of armor?
01:08These six amazing animals use their evolutionary advantages to carry, climb, squeeze and fight their way to a full belly
01:17and reproductive success.
01:18These are the strong men.
01:23Leopards are well known for their sleek beauty and lightning speed.
01:28As a species, they're a real success story.
01:32Leopards are part of the big cats, which are cats that have the ability to roar.
01:38Leopards are found in Sub-Saharan Africa, Northeast Africa, Central Asia, India and China.
01:44A leper is actually adaptable across a lot of different habitats.
01:48Open grass, dense forest, they are an ambush predator.
01:53They're built for camouflage.
01:55They can literally sit there for hours waiting on a prey, just camouflaging.
02:00Whether it's a leopard in Africa or a snow leopard in the mountains,
02:03it could take you hours to even see that little tiny head or that big body in those spots
02:09because they're perfectly adaptable for each situation.
02:12And that's what makes them so successful in hunting.
02:15Leopards are generalist predators.
02:17They can prey on 90 different species of animals.
02:20Birds, rodents, but also a lot of ungulates like gazelles, antelopes, even young giraffes.
02:30They're one of the smaller of the big cats, not as large as the lion.
02:34But when it comes to brute strength, leopards have an advantage over other big cats.
02:40They've got a huge power to weight ratio.
02:42And so that allows them to do things that other big cats can't.
02:47You don't see lions and tigers in the wild climbing trees.
02:51Leopards are roughly half the weight of their big cat cousins, the lion and tiger.
02:56When we look at the energy and the force required to move objects up and down,
03:01it's very much related to mass.
03:04So the energy associated with mass at height is mass times gravity times the height.
03:10So if your mass is lower, you're going to be able to use less energy to lift yourself up.
03:15So it's an evolutionary advantage to be strong and lightweight for the leopard to be able to climb.
03:21Not only do you see them climbing trees, but they do it with an animal or prey in its mouth,
03:26and not just a small animal.
03:28Sometimes they'll have antelopes.
03:31Tree climbing is part of the leopard's hunting strategy.
03:35They are able to carry a carcass three times their own weight up into the branches.
03:39When you add a completely dead weight, and not a smooth dead weight, a dead weight that can catch on
03:45limbs and branches
03:47and may need to be pulled and shoved in different directions, this becomes an astonishingly difficult feat.
03:54The spots in their fur, called rosettes, help camouflage the leopard in the branches.
04:00But what advantage does tree climbing give the leopard?
04:03Leopards spend a ton of energy, like most predators do, to kind of make a kill in this opportunistic way.
04:08But also they've invested a ton of time into each kill.
04:12Unlike a lot of big predators that can plan multiple attacks all the time,
04:15there's longer stretches between advantageous moments for something like a leopard.
04:19That ability to climb allows them to protect their meal from hyenas, lions or any other competition.
04:26That adaptation could also help them secure prey that are climbers as well, and expand their generalist diet.
04:36Evolutionary engineering has endowed the leopard with a physiology specific to this task.
04:41If you look at a leopard compared to a cheetah, a cheetah is built for speed.
04:46The frame is lightweight, you've got the paws that barely touch, you've got a long leap,
04:51and when it stretches out, it's actually quite long.
04:53When you look at a leopard, they're built literally to climb and hang,
04:58and just move things going up instead of going horizontal.
05:03It's actually more compact.
05:05The front paws are a lot bigger.
05:07The shoulders are bigger, the chest is bigger, the bones are bigger.
05:10There's a lot more muscle.
05:12He needs that upper body strength, that strong neck, the powerful jaws, the powerful shoulders,
05:17so that it can carry its prey to the tree and climb up the tree.
05:22Leopards have strong, muscular back legs that they use to push their bodies upward.
05:27Those powerful muscles also allow the leopard to excel in its unique hunting style.
05:32Leopards operate using a pounce technique.
05:35They come close to their prey about five to ten meters,
05:38and then they attack by a bite to the neck, asphyxating them.
05:42When you have a predator that is built front heavy,
05:45the sit and pounce sort of method of hunting really works well.
05:50It's sitting there, crouched down.
05:52Once it pounces, it's all about strike force,
05:55and as long as its bite is bigger than its bark, it could really crush anything.
06:01Once the prey is caught, the leopard has a few other ingenious strategies for getting its meal to safety.
06:08One of the interesting things that they'll do is after a leopard has killed a prey item
06:13is they will disembowel that prey item
06:15and leave a lot of the internal organs where the kill has occurred.
06:18And that works really well in two ways.
06:20First of all, leaving a bunch of organic matter, rotting matter,
06:24will attract things like scavengers and other predators to that site
06:27as opposed to the site where they're actually keeping their tree.
06:29So it's a little bit of bait and switch.
06:31The second thing is it means that the prey item is now like lighter
06:35and they have just a lighter load to carry and drag back up into the safe place,
06:39which is their personal tree.
06:41The leopard's claws are part of their design for climbing the tree.
06:45One of the great evolutionary advantages of cats,
06:48and specifically leopards, is the retractable claws.
06:51Having really long claws and really big paws gives you a very large area of purchase.
06:57So the leopard is going to grab onto the tree and have a very large base to work with
07:01when it pulls itself up.
07:02If you imagine that you were just grabbing in one spot,
07:05you have a much higher propensity to slip.
07:08Whereas if you have your claws extended over a wide area,
07:12if one claw is as gripped into the tree as another one,
07:15you're still not going to lose that grasp of the tree,
07:18that purchase, that ability to hold on.
07:20And leopards can climb back down the tree head first.
07:23Head first climbing down allows you to see where you're going.
07:27Backing down a tree, you're always looking for your foothold,
07:30trying to figure out where you're going to put your next foot.
07:33And you're always going to have an obstructive view,
07:35which makes it particularly difficult.
07:37Being able to go down head first means you always see where your next footfall is.
07:41You can often do it at much higher speeds.
07:44So there's a lot of advantages to that for the leopard.
07:47Human engineering can only dream of achieving this level of strength and agility.
07:52As engineers and scientists, you know,
07:54we are really trying to achieve what biology is essentially perfected.
07:59And climbing is maybe the ultimate goal of robotics.
08:02You know, you'd think that flying would be more difficult than climbing,
08:05but flying is pretty easy.
08:06You know, you just avoid obstacles and you're fine.
08:08Whereas with climbing, you've got to look for a handhold.
08:11And it's not just going and grabbing it,
08:13it's reaching around and using a claw-like motion
08:16and digging into that surface and making sure you're holding on.
08:19All of that biological engineering is in the leopard.
08:23It's got this great set of physical attributes that as engineers we aspire to achieve.
08:29It really allows you to gain a big respect for these animals who can do it all on their own.
08:35I mean, I don't think I can lift my child up a tree.
08:38You know, I can barely lift myself up a tree.
08:40Even if it was for my survival, I don't think I could bring something up to eat.
08:44Like a steak dinner or something. I just don't think that would happen.
08:48Using brute strength to carry prey is impressive enough.
08:52But another incredible creature uses its massive power for only one purpose.
08:59Constrictor snakes, like the boa constrictor and the python,
09:02are so named because they use their incredible musculature to constrict their prey.
09:07Which leads to the biggest misconception about them,
09:10that they kill by crushing or suffocation.
09:13When they squeeze, they disrupt that blood flow of their prey.
09:17That could lead them to being deprived of oxygen to their brain called ischemia.
09:22And that is eventually what kills them.
09:24The deadliest constricting pressure ever measured was 172 kilopascals,
09:30which is roughly the pressure needed to break a human neck.
09:33The average pressure a boa constrictor exerts is 41 to 83 kilopascals.
09:38It depends on size of the actual snake.
09:41Every time you double the diameter, you're adding 2.6 more times the pounds per square inch.
09:46Those pythons you see at shows that people are holding, they're like 10 feet long,
09:50and you just see these massive diameters, they're going to have quite the squeeze.
09:56Constrictor snakes are really amazing in that they're using their entire body,
09:59from the head all the way down, in order to catch their prey and kill it.
10:04Most other animals that have a strategy that relies on strength
10:07will kind of put a lot of energy towards a particular set of muscle groups that enable a behaviour.
10:13But being strong throughout is a really amazing situation, and it's not very common.
10:18They look benign because they generally don't move fast.
10:21It's actually far from the truth. They're among the strongest animals in the animal kingdom.
10:25Boas and pythons are some of the largest snakes in the world.
10:29They have evolved to look remarkably similar, even though they're not related,
10:33due to a phenomena known as convergent evolution.
10:36Boas live in Central and South America, while pythons are found in Asia, Africa and Oceana.
10:42Both have evolved to do one thing really well.
10:45Every time that animal breathes out, the constrictor constricts a little bit more,
10:50and then they can't breathe in again, and constricts a little bit more,
10:53and finally it gets to the point where the animal runs out of oxygen.
10:58That deathly strong squeeze is designed for constrictor snakes
11:01to capture and keep more fast-moving prey.
11:05Hunting when you're a snake is very difficult,
11:07especially if you're a slow-moving snake, like a constrictor.
11:10The average is one mile an hour.
11:12So you are vulnerable to any outside attack, not only from your prey,
11:17but any other predator that wants to eat you instead.
11:20When you constrict, you want to make sure that your prey is subdued so they can't get away.
11:26That slow, steady movement is the result of the constrictor snake's impressive musculature.
11:31This isn't just one muscle, it's many, many muscle groups working together,
11:37and bones and cartilage to latch those muscles on to achieve what you need to do.
11:43Constrictors are boreal, so they're climbing trees and moving through the canopy to be able to coil around a tree
11:49and find limbs to grab onto and then move your body up from that point.
11:54And it takes a lot of muscles.
11:56Snakes are really amazing from a motion point of view,
11:59and as an engineer we would love to replicate that.
12:01Trading speed for strength has led to other necessary adaptations.
12:06These snakes are ambush predators, they don't spend a lot of time hunting,
12:09and they only really exert that energy when they are squeezing their prey.
12:13They have a stealth mechanism by which they need to kind of sneak up on a prey item without it
12:19noticing,
12:20maneuver kind of slowly into place.
12:22Evolutionary engineering has given constrictor snakes another advantage.
12:26Curved front teeth that act as grappling hooks.
12:31When a prey crosses the path of a snake, it'll strike and it'll sink its teeth into the prey.
12:37That first strike, that first bite, is essentially, I would think, a scare tactic.
12:43If I'm a prey, one, it hurts, and where did this thing come from?
12:47You know, so you're a bit in shock.
12:49The other point is that anchor point,
12:51so the snake can actually wrap itself around and then start constricting.
12:56But the evolutionary advantage constrictor snakes gain from their massive strength has a cost.
13:02They have to consume their prey as fast as possible.
13:05Their most vulnerable moment is probably when they're eating and after they've eaten.
13:09Imagine you've just killed something enormous.
13:12It's taken a huge amount of your physical energy throughout your entire body.
13:15When the snake starts eating the prey, it doesn't have any limbs to push it in.
13:19So it has these pterygoid teeth that essentially act as a conveyor belt to bring the animal closer into its
13:25body.
13:26So basically down the hatch, if you will.
13:28Pterygoid teeth are an inner row of curved teeth that move separately from the jaw
13:32and literally walk the prey whole into the constrictor snake.
13:36We have all heard those stories of, you know, people finding a cow or a goat or something inside these
13:42constricting snakes.
13:43The digestive capabilities that they have to just break down an entire animal without any mastication
13:48or taking it apart in any way before it enters their body and just kind of liquefy it down into
13:53its parts
13:54and use that energy takes, in some cases, weeks.
13:58And a lot of its energy is going towards this incredible work of breaking down this enormous prey item in
14:04its body
14:04so it doesn't have a lot of energy for other things.
14:07In the case where they are faced with a predator or competition or any threat in general,
14:13they actually regurgitate their prey because having that heavy body inside of you can impede your movements.
14:20This type of hunting behavior is quite efficient because they don't have to hunt all the time.
14:26Some snakes even just hunt about 12 times a year.
14:30While constrictor snakes squeeze with brute force, they also have remarkable tactile sensitivity
14:37that they use to monitor their prey's heartbeat.
14:40When you're a snake and you are constricting your prey, you're restricting their blood flow.
14:46You want to be able to tell how well you're doing and you can sense how fast the heart is
14:53beating.
14:53Then you know how much more you have to constrict or if you can let go or if you can
14:59start the feeding if the heart rate is nothing.
15:01And so that allows them to just become that much more of an efficient predator.
15:06This tactile sensitivity has interesting implications for human adaptation.
15:11What if we could use constrictor snakes to detect seizures by monitoring blood pressure?
15:17The ability that they have to sense kind of minute changes through the surfaces of their skin.
15:21There are so many different applications that we as people could apply that ability to.
15:26I can't even imagine what that would open up because currently when people want to get that kind of biofeedback
15:33and understand what's happening in a biological system, it's incredibly clunky.
15:37It requires like multiple machines, often delays as well.
15:41And so yeah, the utilizations would be almost endless.
15:43Constrictor snakes are one of nature's strongest and deadliest predators.
15:47But there's one species that has been bioengineered to use its superhuman strength for defense.
15:54Meet the thickest skinned member of the animal kingdom, the rhinoceros.
15:59They have a really thick layer of armor, 1.5 to 5 centimeters thick.
16:03So this is, you know, from this thick to about that thick.
16:06This isn't a small amount of skin.
16:08This animal is built to take a beating and keep on going.
16:12Rhinos can weigh close to 3,500 kilos and can be just under 2 meters in height.
16:18They are some of the largest and toughest mammals walking the earth.
16:21But it's their skin that makes them the armored tank of the animal kingdom.
16:26This type of skin is not something you normally see in large mammals.
16:32Hippos don't have it.
16:34Elephants will have thick skin, but not as thick as this.
16:37This is unique to the rhino species.
16:40Rhinos are little tanks, essentially.
16:43Squat, low to the ground, basically impervious to pretty much any disturbance.
16:49You know, they have a very rough life.
16:51The elements that they're in, the bugs that they encounter, the sun that they're in.
16:57They have to have a thick skin in order to survive that type of lifestyle.
17:02That tough armor-like skin is one of evolutionary engineering's great success stories.
17:09Rhinos have been roaming the earth for at least 50 million years.
17:12Both woolly mammoths and woolly rhinos were kind of created by this Ice Age steppe environment in Europe.
17:19The longer an animal's around, it usually indicates that there's something in their genetics that's giving them a huge advantage
17:26over the other animals that they're competing with.
17:28As engineers, we love to stick with tried and true designs.
17:32We know it works, it's proven, let's stick with it.
17:34And the animal kingdom's much like that as well.
17:37Rhinos are part of the group Parasodactyl, so odd-toed ungulate.
17:41So tapirs, horses, zebras, and the rhinos.
17:44Their skin is one of the toughest materials around.
17:47And unlike their armored cousins, the armadillo and the pangolin, rhinoceros' skin is made up completely of layers of collagen.
17:55Collagen has fantastic tensile strength and elasticity.
17:59And rhinos take it to the next level.
18:02In a rhinoceros, collagen layers are criss-crossed along each other, almost like a 3D matrix.
18:08So it provides that toughness.
18:10We know that things with lattice structures tend to be stronger.
18:13They're kind of mutually reinforcing within the structure.
18:15Collagen is one of the essential building blocks for skin and cartilage in all mammals.
18:21It consists of amino acids bound together to form a triple helix of elongated fibrils.
18:28That collagen fiber is making that skin like carbon fiber reinforcement.
18:33It's kind of like an engineered armor.
18:35The fibers meshing with each other in bundles and overlapping each other creates kind of a network of high-strength
18:41material
18:42that's bonded together that when it gets impacted, instead of it just impacting here, it's spreading that load over the
18:49entire area where the impact occurs.
18:51It's like a football player's shoulder pads.
18:54And just like a football player's shoulder pad, a rhino's skin is thickest in the shoulder area.
19:00It just looks like somebody has taken a coat and put it on a rhino.
19:05The skin thickness can range from 45 millimeters on the shoulders and back all the way down to 10 millimeters
19:11on the belly.
19:12It has these layers.
19:14It has folds in and around the limbs.
19:16It'll have folds along the back.
19:18It's so primitive-like that you almost wonder how it developed or how it kept such a thick skin.
19:25Their armor, while it keeps them safe, also has some constraints where it keeps in a lot of body heat.
19:30Evolutionary engineering came up with an ingenious cooling system for the rhino.
19:34They don't have this thick armor-like skin throughout their entire bodies.
19:39They just have it kind of where it counts.
19:41So in their movable folds and on their undersides, they have a lot thinner skin, and that allows them to
19:46kind of thermoregulate.
19:47This area of their skin actually has a lot of peripheral nerves and vasculature that allows a lot of blood
19:53flow into it, allows them to effectively thermoregulate.
19:56You'll see the folds of the rhinos have more of that surface area, and that's how they're able to release
20:01that heat.
20:02They don't have to be a tank everywhere.
20:04They can keep cool and be tough on the outside as well.
20:07The rhino's extreme vasculature results in a surprising amount of sensitivity in the skin.
20:13Which is why you see a lot of rhinos rolling in the mud, protecting themselves from insects, because they can
20:19get quite irritated with this because of the amount of nerves in that area.
20:23That sensitivity makes the rhinoceros skin the ultimate strongman paradox, when you consider how extraordinarily tough that armor is.
20:32A crocodile bite is 16,000 newtons. It's almost impossible to open up a jaw once it's closed, because the
20:38force is so much.
20:39The armor of a rhinoceros can actually withstand a million newtons.
20:45Trying to penetrate the force of rhino skin, it's virtually impossible.
20:51Rhino skin is about half the strength of steel, so this armor is very, very strong.
20:58But not only is it strong, it's tough.
21:00One of the problems with steel is if we impact it, it dents or fractures or breaks.
21:05With the rhino armor, not only is it strong, but it's flexible and durable.
21:10So it's really, really an amazing material.
21:13Rhinos are herbivores, so they don't hunt.
21:16And they are so massive that they have few predators.
21:19So why do they need such a tough skin?
21:22The answer is other rhinos.
21:25A group of rhino is actually called a crash, and it doesn't take a lot to grow as to why.
21:30Once these adults hit that sexual maturity, it's all about breeding for them, and males have certain territories that they
21:37guard.
21:38And females are free to roam around whichever area they want.
21:41And when they do see males confront each other at each border of their territories, females are able to assess
21:47their reproductive success.
21:49Does this male have good genetics? Is it going to be compatible to me? Do they have the strength? How
21:55well is their territory defended?
21:58They have basically a 50% chance of being successful and getting a mate, and the other 50% chance
22:02is potentially fatality.
22:05You're essentially having two substantial-sized pickups with a load in them hitting each other.
22:10If I take two pickup trucks going 20 kilometers an hour and then crash them into each other, that's going
22:16to be pretty catastrophic.
22:17If you had those kind of impacts being passed on to those internal organs, to the ribs, to the bones,
22:23etc.,
22:23they would probably die or at least sustain injuries that would prevent them from procreating or being a successful member
22:30of their species.
22:31The rhino's horn is a deadly weapon made from keratin, the same material in human hair and fingernails.
22:38It's one of the few things sharp enough to gore rhino's skin.
22:42A rhino's horn, unlike the way that we have keratin in our own bodies, which is highly bendable,
22:47is in a much more kind of rigid, crystalline structure, which allows it to withstand more forces
22:52and allows it to be a threat and to be a weapon in this case.
22:55And that's kind of the rhino in a nutshell.
22:57Taking things that other mammals have, nails, skin, and just taking all of those very familiar ingredients of your average
23:05mammal
23:05and really pushing the envelope on what that substance can be.
23:10As humans, we have developed ways to mimic the impressive strength of rhino skin.
23:15You look at the armor of a rhinoceros and you see the very similar sort of materials that come about
23:24in a lot of different products.
23:27Hard products like vehicles and that type of structure to plastic and rubber type of materials that will provide protection,
23:36that will provide flexibility.
23:39You don't think of these just out of nowhere.
23:42We observe them in the wild and we say, how can we duplicate this to fit our needs?
23:47Blasting mats may be a very good analogy for the rhino armor.
23:51So if we want to make a new roadway, we don't want, when we blast, all the rocks to go
23:56into the neighborhood.
23:56So what we do is we take a series of mats that are essentially rope fibers that attach rubber blocks
24:03together.
24:04And then we stake that to the ground.
24:06And when the blast occurs, the rubber and the ropes all stretch and absorb the energy of the blast so
24:12that the rocks slow down and then essentially remain in the same area where the blast occurred.
24:17What the rhino skin is doing is kind of the same thing.
24:20They're absorbing the impact from the fight they're having with their competitor and distributing that energy so it doesn't impact
24:27the inside of the rhino itself.
24:29But we still have a long way to go to match nature's incredible engineering.
24:34If there's a will, there's a way.
24:36With biology, it always kind of finds the best solution that it can, balancing energy constraints and the need for
24:43protection and longevity.
24:45Biology is really, really amazing at solving complex engineering problems.
24:53Lurking in the murky waters of the savannah, there's a creature with super strength that comes down from the age
25:01of the dinosaurs.
25:02Only this family of strong men survived even that extinction.
25:07Crocodiles are considered one of the strongest animals on the planet.
25:10Their bite can generate a force of 3,700 pounds per square inch.
25:16Crocodiles are kind of like an ancient set of technology from a biological perspective.
25:22And we've never really been able to design something that can do what a crocodile does.
25:26One of evolution's greatest survivors, the crocodile, has been around for over 80 million years.
25:32They have a wide geographical range and can be found in the tropical habitats of Africa, Asia, Australia and the
25:39Americas.
25:41One of its species, the saltwater crocodile, is the biggest reptile on Earth, although their ancestors were much bigger.
25:49They've been around since dinosaurs.
25:51There were a lot of predators back then.
25:54You had to have very thick skins, which crocs definitely do.
25:58And you had to have a very big bite force.
26:02In fact, modern crocodiles have the strongest bite force ever recorded.
26:06About 1,600 kilograms of force, or more than a ton of force that the crocodile can close its jaws
26:12with.
26:13So if you were clamped in those jaws, you would literally have to use the strength to lift an automobile
26:19off of you.
26:20There's nobody on Earth who has the strength to generate that kind of force.
26:24But that evolution is entirely designed for closing strength.
26:29It has no strength in the opening direction.
26:31An average man can pull the crocodile's jaws closed quite easily, but there's no way you're going to be able
26:37to pry that back open.
26:39There's no way you'll forget that sound either, which is like nothing else in the animal kingdom.
26:44It has been likened to hearing a gunshot.
26:47It really is a very loud snap and very distinctive.
26:51In the wild, the gunshot sound is even more striking because of the relative quiet that precedes it.
26:58Crocodiles have mastered the art of being stealth predators.
27:02You'll see them slowly inching towards their prey, just having their eyes, their nostrils just peeking at the top.
27:08It doesn't rush.
27:11Crocodiles are cold-blooded animals.
27:13And one of the things cold-blooded animals can't do is maintain energy output for long periods of time.
27:19Endotherms can store a little bit of energy in their muscles and expend it relatively quickly.
27:24But then it's very difficult for them to replenish it quickly and reuse it.
27:29Crocodiles are carnivores, and they are semi-aquatic.
27:32In the wild, they generally feast on fish, birds, frogs, and crustaceans.
27:38They can also attack large prey.
27:40They'll wait, you know, until terrestrial prey comes to the water's edge.
27:44And that's when they strike.
27:46That tail of the crocodile is immense.
27:49It's like a giant paddle that basically shoots the crocodile like a torpedo.
27:54And then the jaws clamp very quickly onto that prey.
27:58And then they'll bring it to the water to do what's called this death roll, whereby they are clamped into
28:03it.
28:03They're drowning this thing in the water really quickly.
28:06It's being rolled in three dimensions under the water.
28:09They don't even know which direction to fight anymore because they have no sense of directionality.
28:14Ironically, the strongest biter in the animal kingdom does not actually chew its food.
28:18And similar to how birds ingest grit, many crocodiles swallow stones to assist in the crushing of food.
28:25Essentially, the croc is a tear-and-swallow type of predator.
28:30They will literally rip apart and they will just swallow large pieces to get them down.
28:35While its attacks on smaller or aquatic prey might not be as spectacular,
28:40the crocodile still brings a trove of evolutionary tweaks to get the job done,
28:44such as its special palatal valve.
28:46This can prevent water and smells from entering its throat
28:49and is why the crocodile can keep its mouth open at any time under water.
28:54They can also track prey by vibration.
28:57Crocs have these nerves in the bottom part of the jaw where they can feel the vibrations of prey moving.
29:03They can also see that prey very well when it gets close.
29:07They have two sets of eyelids, one that allows them to see under water
29:10and one that allows them to see on land.
29:13Perhaps the most incredible piece of biological engineering to do with this super biter
29:17was only discovered in 2016.
29:20Using computer modelling, a team of researchers was able to show the intricate network
29:25of bone, muscle and cartilage in the jaws of this creature.
29:28They also determined there was a secondary jaw joint.
29:31Their secondary joint in their jaw allows them to distribute the force that they generate throughout its skull
29:37and prevents the crocodile's jaw from twisting or moving around when it's feeding.
29:42The crocodile's secondary joint is similar to the temporomandibular joint in humans,
29:47the hinge that connects the lower jaw to the top of the skull.
29:51Amazingly, the crocodile's secondary joint does not suffer arthritis despite the force it is subjected to.
29:57Crocs have this amazingly strong cartilage.
30:01Not only does it have to be strong, it has to be tough.
30:04And toughness is the ability for a material to resist tear or fracture under sudden loads or high loads.
30:10That cartilage that's in the crocodile is very resistant to tearing under really high loads.
30:17And that has great applications not only designing better plastics and polymers and structures,
30:21but also in bioengineering for replacing ligaments in knees or legs or elbows or shoulders or what have you.
30:27Because if we can design those ligaments to resist tearing better,
30:31those people that are using those replacement ligaments will be much less likely to experience another injury.
30:38The crocodile may hold the title for the creature with the strongest bite, pound for pound,
30:43but the bone-crushing bite of this small marsupial comes in for a very close second.
30:50The Tasmanian devil has the strongest bite of any mammal.
30:54It's also, along with the hyena, one of only two mammals whose jaws can cut through bones, a natural bolt
31:01cutter.
31:02Currently, this legendary creature's habitat is restricted to the Australian state of Tasmania,
31:07but not for much longer.
31:09And to understand its future, it's worth looking at its recent past.
31:15It got its name in the early 19th century.
31:18European settlers in that area discovered the animal by hearing the growls and vocalizations that it made.
31:25Not only did they have a devilish sound, but they had devilish behavior.
31:31Livestock's a really easy target for them.
31:34So when the first settlers were going to Tasmania and you wanted to raise your chickens,
31:38well, I think the Tasmanian devils probably had something to say about that
31:42and decided that the chickens were pretty yummy.
31:44Tasmanian devils are about the size of a dog or a bear cub.
31:47They're considered the largest carnivorous marsupial,
31:51which are animals that have that pouch similar to kangaroos, wallabies, and koalas.
31:55The animal kingdom was once populated by a wide variety of carnivorous marsupials,
32:01some of them huge, but few species remain.
32:04The Tasmanian devil emerged 10 to 15 million years ago
32:08and once had a much larger habitat.
32:113,000-year-old fossils in mainland Australia suggest they used to be common there, too.
32:15One theory for their expulsion is the dingo,
32:18which was introduced to Australia around that time.
32:21The competition from the dingo may have wiped the devil out.
32:25However, in Tasmania, they are holding it down.
32:28There are apex predators in their area
32:29and have been known to regulate the populations of other animals.
32:35Part of what makes them apex is that their frightening and frenetic behavior intimidates others.
32:41There are a few predators, eagles, quolls,
32:44but I would not want to be in a one-on-one battle with a Tasmanian devil.
32:48They're extremely aggressive. They go for head bites.
32:52You've got the combination of aggression and the odor that they emit,
32:56which is very similar to a skunk that we all know and love.
32:59It's quite a powerful smell.
33:00And so it's very off-putting for a predator to have to deal with smell and aggression.
33:08In terms of how it attacks, it does so by pummeling its canines into its prey's skull
33:13and delivering a frenzy of bites, effectively damaging the brain.
33:18Every part of the body is permeable to them.
33:20It makes sense to just go for the skull, get into the brain with your teeth,
33:25and then it's dead really quickly, and your hunt is done.
33:29As for what the devils themselves go after, pretty much anything.
33:34Metabolically speaking, nothing uses up as much insane energy per unit of time as a Tasmanian devil.
33:42They literally are just energy powerhouses.
33:45They have this very explosive hunting style, but that means that in order to maintain that explosive style, they need
33:51to fuel it.
33:52These animals can eat about 15% of their body weight per day.
33:57That's equivalent of a 150-pound person eating 22 pounds of food a day.
34:05When you look at Tasmanian devils, you think, wow, that's a lot of teeth.
34:10Like a dog, the devil has 42 teeth.
34:13But the devils grow continuously throughout its life.
34:16The root of its tooth goes really high into the skull, which makes it even tougher to break.
34:21And so it allows it to have that extra pressure to break bone and crush bone.
34:25It also has the ability to open up its jaw about 80 degrees.
34:29So if you think about your own human mouth, it can really open up maybe 45, 50 degrees.
34:3380 degrees is a huge jaw opening angle.
34:36It really means that you can get your head around very large prey.
34:40Not just grab its legs, but really make one solid bite that's going to finish off that animal.
34:46So having a jaw that opens really wide is advantageous to take on prey that's your size or larger.
34:52Importantly, as well as going after live animals, Tasmanian devils also go after dead ones.
34:58They are scavengers, the clean-up crew of the island.
35:02And this is where their bolt-cutting jaws come in particularly handy.
35:05They're not just eating the muscle mass or a few of the internal organs.
35:09They also eat the bones.
35:11There's a big evolutionary advantage to animals that do crush bones and eat the bones
35:15because the marrow inside the bones is among the most energy-laden food sources that an animal can have access
35:22to.
35:23If you look to Sub-Saharan Africa, the hyenas crush the bones of their prey to make sure they're getting
35:28to the marrow.
35:29And in Tasmania, the Tasmanian devil is doing the same thing.
35:32Few animals eat bones because few need to.
35:36And few animals have the jaw strength to easily crack them open to extract the marrow.
35:40But for scavengers like the devil or hyena, the marrow is dietary gold.
35:47If you look at the very strong, square shape of the Tasmanian devil's head,
35:53you can see that there's a lot of structure where the muscles attach to the jaw,
35:57giving them a real mechanical advantage to being able to crush bone.
36:01Tasmanian devils, they're not really going to be good pets.
36:04They've actually been found their jaw is so strong that they can bite through a steel cage.
36:08If it does get caught or has to be relocated,
36:11that's something that scientists and researchers have to be aware of.
36:15Knowing how aggressive this animal is, you don't want that to happen.
36:19In fact, scientists have recently been relocating these creatures
36:23and reintroducing them into the wild in Australia.
36:27Why? Because on the mainland, invasive red foxes and feral cats
36:31have been devastating the small mammal populations.
36:34And for years, conservationists have zeroed in on the devil's crucial scavenger role
36:39in maintaining a balanced, healthy ecosystem.
36:42Now, after hundreds, perhaps thousands of years,
36:45they are returning to their ancestral homeland.
36:48The scientists are confident that they'll prevail.
36:51When you're a scavenger, like the Tasmanian devil,
36:54you're extremely adaptable.
36:56They've been through a lot.
36:57Climate change has really affected their distribution,
37:00but the fact that they can literally eat anything,
37:04whether it's alive or dead, allows them to persist in where they are now.
37:08Some of these creatures are truly imposing in size and strength.
37:14But to find the strongest animal, you might be surprised where to look.
37:20Big things sometimes do come in small packages.
37:24And with the capability to pull over a thousand times its own body weight,
37:28the dung beetle holds the title of the strongest insect and, pound for pound, strongest animal.
37:36A dung beetle is moving over a thousand times its own body weight.
37:41That's like equivalent to a human pulling like six double-decker buses.
37:45It's just not going to happen. And the dung beetle does this every day.
37:49This beetle uses its titanic strength to create and move balls of dung.
37:54Waste, poop, scat, dung. Yeah, we human beings tend to think of it as a waste product in a modern
38:01era,
38:02but it is an incredibly important kind of resource, both chemically and energetically.
38:07And dung beetles have really kind of taken that resource
38:09and they've specialized in utilizing it in a really efficient way.
38:13Dung beetles have been around for about 130 million years.
38:17They're highly adaptable.
38:19Today, there are 7,000 species of them on every continent on Earth except Antarctica.
38:24They are one of evolution's most intriguing success stories.
38:28Dung beetles are, in a way, nature's garbage collectors.
38:32The wildebeest and zebra and elephants, they put their waste on the plain.
38:37The dung beetles take that waste, roll it up by tons and tons and tons,
38:42stick it underground where it composts and adds to the nutrient value in the soil.
38:47That regrows the grass that then the wildebeest and zebra eat.
38:51They have evolved a digestive tract system that allows them to exploit this in a way
38:57that they get enough food for it.
38:59So even though it's been ejected by somebody else,
39:02it's still good enough quality and has the nutrients in it for the offspring of the beetle.
39:08These beetles can move one metric ton of dung per year.
39:12If there was no recycling and management of waste in our ecosystems,
39:15very quickly we would literally, in the world, be drowning in this stuff.
39:21Like all insects, the dung beetle has an exoskeleton.
39:26You grab hold of it, it's really hard. It won't squash easily.
39:30This hard shell both protects the beetle and helps regulate temperature.
39:34One of the things is they're dark, they may be reflecting heat,
39:38but they also can open up their spiracles, which are the little holes where the air goes in and out.
39:43And they can lose heat by evaporative cooling.
39:46But then they also lose water.
39:48So at night, what they do is they sit with their backsides up in the air.
39:52On their wings, they have these little gutters.
39:55And when it gets cool, you get condensation and it dribbles down towards their head so they can drink it.
40:01It's kind of outside our human reality.
40:05I mean, we are really designed to work in a really small envelope.
40:08If the temperature drops below 20 degrees Celsius, we need a shirt on or we're going to get cold.
40:13If the temperature goes over 40 degrees Celsius, we're not going to be standing outside in the sun.
40:18And if it hits 50 degrees Celsius, our lives are threatened by those kind of temperatures.
40:24The dung beetle can operate in a much larger range and in some places up to 60 degrees Celsius.
40:29Really amazing evolutionary advantage.
40:31Dung beetles have evolved into four distinct classes.
40:34And the first one are the dwellers.
40:36These are the ones that live in the path themselves.
40:39They lay their eggs there.
40:41They live there.
40:42It's quite efficient.
40:43There's an abundance of food.
40:45However, it can get messy and their eggs might get destroyed in the process.
40:49The second ones are the tunnelers.
40:51These are the ones that excavate tunnels underneath and create their brood balls or the food balls and store them
40:56down there.
40:57And the third ones are the rollers.
41:00These are the ones that are mainly found in Africa and Australia.
41:03They roll the manure into big balls and they transport them to a different place where they can feed on
41:09it later.
41:10And then interestingly enough, the last one are the kleptomaniacs, which are the ones that steal the already made balls
41:16by other dung beetles.
41:19It's the rollers who are the strongmen of the dung beetle world.
41:22And the bullheaded dung beetle is their weight lifting champ, built for power.
41:27Their small size is part of what allows them to be able to kind of do these amazing feats of
41:32strength.
41:32The ability to kind of move and push items that are much larger and much heavier than yourself is easier
41:38if you're smaller.
41:39Larger animals need to use more of their strength to support their greater muscle mass.
41:44The smaller, lighter dung beetle can devote most of its strength to its task.
41:49They're incredibly well designed to move something so large compared to their own mass.
41:54In some ways, the dung beetle is nature's bulldozer.
41:57Their heads have a sharp edge for digging and carving out dung.
42:01And they use the serrations on their front legs for raking and scraping the dung together to form a ball.
42:06They're short and stocky and they've got very big legs, not spindly legs.
42:11When you're on a tilt like that and you're pushing, the force that you're getting behind it is much more.
42:17Using this brute strength to move their dung ball around allows them to protect it from thieves and other hazards.
42:24But the main reason the roller beetle creates and moves these dung balls is to attract a female.
42:30Once a female dung beetle finds the ball she likes, she hitches a ride.
42:35What they do is they then bury it and the female will lay an egg in it.
42:40Males have quite a tough job because the female actually lays one egg per ball.
42:45A female can lay up to 60 eggs in a season, meaning that male has to then create 60 balls.
42:51Most insects will have a lot more offspring than 50 to 60.
42:55But if you are constrained by using this dung resource and doing this incredible physical labor,
43:00that's probably a large part of the reason that they have so few offspring for an insect species.
43:05So the more balls that you can roll, the higher chance you'll be able to fertilize the eggs and be
43:10able to then pass your genes.
43:11That is an insane constraint. But there is a payoff for it because when you're young,
43:16enter into their larval stage and the egg hatches, they have access to just an incredibly rich resource.
43:22The larvae actually consumes 40 to 55 percent of that dung ball that they are laid in.
43:27So the parents spend a lot of time investing in creating an optimal environment for growth.
43:32It is critical for their survival.
43:35It takes massive strength to carve out, roll, and bury these balls.
43:40And then to fend off competitors.
43:42There are the kleptomaniacs, which are probably my favorite.
43:45So if another dung beetle, like a roller, is moving a pat from one place to another,
43:49that kleptomaniac is going to come in and steal that.
43:52So it's got to be quick. It's got to be ready to fight.
43:54They fight. Many dung beetles have horns on the front end of them, part for shuffling the poop, but also
44:02for interactions with others.
44:04And I mean, they will get quite aggressive. I will get you out of here. This is my turf.
44:09These amazing feats of strength have earned these ecological engineers the title strongest animal in the world.
44:15As humans, we think we have a lot of strength, but in the animal kingdom, we're really not the strong
44:21men, you know.
44:21In engineering, to get that kind of energy and power into such a small package on the scale of what
44:27the dung beetle does is very difficult.
44:29The dung beetles are absolutely amazing.
44:32Whether the toughness of the Tasmanian devil's bite or the strength of the leopard or the boa constrictor, the animal
44:39kingdom continues to inspire us.
44:41We look to a variety of different systems to try and figure out what their advantage is and how they're
44:48achieving either the strength or power in different ways.
44:52Not only do we learn more about how they work and survive, they give us clues on how we and
44:58our technologies can be stronger, tougher, better.
45:11If the
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