0:04 You're probably wondering why you're
0:07 eating these rocks, right? I know, I
0:09 know. You can't help but do it. Don't
0:11 worry. That's perfectly normal. And it
0:13 actually is genius. I'm here as your
0:15 professor to explain all the ridiculous
0:17 calculations your brain's doing without
0:18 telling you. You see, millions of years
0:20 ago, crocodiles figured out how to use
0:22 math and physics for hunting. They did
0:24 it so well that evolution basically
0:26 stopped making updates and has been copy
0:29 pasting the same design ever since. Yes,
0:31 really. The crocodiles we have today
0:33 look strikingly similar to many fossils
0:35 from the last few million years. And
0:36 this trick of eating rocks was one of
0:38 those clever strategies your ancestors
0:40 discovered, making them exceptional hunters.
0:42 hunters.
0:44 But you, well, given that you have a
0:46 prehistoric brain, you found yourself
0:48 doing it without even realizing the true
0:50 reason behind it. Do you remember when
0:53 you were small and dumb? Or rather,
0:56 smaller and equally dumb? You ate tiny
0:57 pebbles to help crush up insects and
1:00 digest better because your actual teeth
1:02 were too pathetic to finish the job. You
1:04 essentially added extra teeth for your
1:06 stomach. But as you grew up, you got
1:08 bigger and bigger. Those rocks stopped
1:10 being about digestion and became about
1:12 something else that you do instinctively
1:14 without understanding why. Eating bigger
1:16 rocks the size of a fist. Some of you
1:18 are carrying around over 10 kilos of
1:21 stones in your gut. But as I said, it's
1:23 not about digestion like it used to be.
1:25 You could swallow a whole gazelle, and
1:27 those rocks wouldn't help. Sit down and
1:30 let me explain. When you fill your lungs
1:32 with air, they act like built-in water
1:34 wings. Every liter of your body pushes
1:36 aside a liter of water. If you weigh the
1:38 same as the water you push aside, you
1:40 flow like a div forced dad in a swimming
1:42 pool. That's physics 101. Without
1:44 something to weigh you down, you'd never
1:47 sink. Each kilogram of rock is 2.7 times
1:49 denser than water. And without rocks,
1:51 you'd last maybe 6 minutes underwater
1:53 before popping up like toast. But with
1:55 rocks, your average dive time nearly
1:57 doubles to 11 minutes. The champions
2:00 among you stretch it out to 35 minutes.
2:03 Your brain just screams, "Eat the rock."
2:04 And you do it because that's what
2:06 evolution figured out 200 million years
2:08 ago. This is why you're stuck with the
2:10 urge without the explanation. This rock
2:12 trick is so old that your extinct marine
2:14 reptile cousins, the plesiosaurs, were
2:17 already doing it 150 million years ago.
2:19 We know this because scientists continue
2:20 to find fossils with stomachs full of
2:22 stones. But it's not only about
2:25 crocodiles. You see, many other animals
2:27 do this even today. For example,
2:29 ostriches for the same reason as baby
2:32 crocodiles to help with their digestion.
2:34 Now, you're probably wondering, "Wait,
2:36 if I keep eating rocks, how do these
2:38 things come out?" Well, here's where it
2:41 gets disgusting. You don't poop them out
2:42 hours later like any normal animal would
2:45 do. No, no, no. These rocks don't take
2:47 the express route. These rocks sit in
2:50 your stomach for a while, weeks, months,
2:52 sometimes even years. Over time, they
2:54 get rounded and smoothed as they rub
2:56 against each other and the food in your
2:58 stomach. Only after that, they start
2:59 taking a luxury cruise through your
3:01 intestines and eventually get pooped out.
3:04 out.
3:05 Oh, and if you're stressed for whatever
3:09 reason, you just vomit them because why
3:11 not? You're impressed, I know, but
3:13 that's just the beginning. Wait until
3:15 you discover more about yourself.
3:17 Speaking of which, let's see what
3:18 happens after you compulsively swallow
3:20 those rocks. As we've seen, they make
3:22 you heavy enough to cancel out your
3:24 lungs filled with air, which means you
3:26 neither sink or float. Thanks to that,
3:28 you're able to hold a perfect periscope
3:29 position, allowing you to literally
3:32 cheat geometry. Thanks to the rocks,
3:33 your whole body stays hidden underwater
3:36 except for two small bumps, your eyes
3:38 and nostrils, that barely break the
3:40 surface. They form a small triangle,
3:42 creating a minimal geometry needed to
3:44 breathe and watch. You know that thing
3:45 where a stick looks broken when it's
3:47 half in water? That's because light
3:49 bends as it passes between air and
3:51 water, or what we call refraction in
3:53 physics. What matters is that this
3:55 phenomenon creates snail's window. It's
3:56 the effect where the bending of light
3:59 forms a circular field of about 97°
4:01 wide, giving you a better view of your
4:04 territory. And guess what? You get to
4:06 see everything without being seen. Yep.
4:08 prey barely sees anything except
4:10 floating sticks that don't look at all
4:12 like a 1500-lb predator because the
4:14 light coming from underwater to the
4:16 surface bends and this bending distorts
4:18 everything beneath it, giving the prey a
4:20 twisted view of what's in the water. I
4:22 mean, that refraction works in your
4:24 favor in both cases. You stay in this
4:26 position for hours, watching and
4:28 patiently waiting for any unlucky prey
4:30 to appear. This constant vigilance over
4:31 the years, you've built up a vast
4:32 archive in your memory about the
4:34 routines of your prey. You know the
4:37 saying, "History repeats itself." You
4:39 live it literally. That archive you've
4:40 gathered helps you predict the behavior
4:42 and needs of your prey according to the
4:44 seasons. Like the birds you've noticed,
4:46 every nesting season, they collect twigs
4:48 scattered around. That piece of
4:50 knowledge sparks a brilliant idea. You
4:52 balance a twig on your snout, return to
4:54 your usual still position, wait a
4:57 little, and soon food comes straight to
4:59 your mouth without effort. The perfect
5:02 example of work smart, not hard. Some of
5:04 your kind living in rivers near human
5:05 villages have watched humans so closely
5:08 that they've learned their routines.
5:09 They know exactly where villagers bring
5:11 their livestock to drink and even what
5:13 time they usually arrive. Using this
5:15 knowledge, they slip quietly to the
5:17 usual watering spots before anyone shows
5:19 up and wait. And through their cunning
5:21 alone, many have gotten the chance to
5:23 taste human flesh. This has turned you
5:25 into one of the animals that kill the
5:27 most humans. And you're also masters at
5:29 shifting your lungs inside your body on
5:31 demand. You see, these balloons are
5:32 basically the steering wheel of your
5:36 body in water. Want to dive down? Easy.
5:37 Scoot your lungs towards your back and
5:39 you start tilting nose first like a
5:41 submarine. Slide them sideways and
5:42 suddenly you're drifting like a shopping
5:44 cart with a broken wheel. Push them
5:46 forward and you go up, rising through
5:48 the water. It's all about lung
5:49 placement. Wherever you shift your
5:51 balloons, the rest of your body tilts to
5:53 the opposite side. That way, your body
5:55 rotates silently without paddling,
5:57 allowing you to fine-tune your position
5:59 with precision while keeping the water
6:01 perfectly calm as you stalk your prey.
6:03 And look, those small, beautiful black
6:04 bumps along your jaw. They give you one
6:06 of the most powerful abilities in the
6:08 entire animal kingdom. Inside each bump
6:10 lies a sensory organ that can detect
6:12 even the tiniest changes in water
6:14 pressure. Finer than the tiniest ripple
6:17 from a single drop of sweat.
6:19 It's like your built-in radar. It allows
6:21 you to sense movement across a wide area
6:24 and pinpoint the exact location of prey,
6:27 even in complete darkness. Let's see if
6:30 it works. Oh, there it is. A tasty
6:33 zebra. A little farther away, but that
6:35 doesn't matter. Using only that tail,
6:37 broad on the sides and packed with
6:39 strong muscles, you slam the water
6:41 backwards, and the water responds by
6:42 generating a counterforce that pushes
6:45 you forward at 20 mph. You don't stop
6:46 until you're right in front of the
6:49 zebra. You open your jaws and lunge,
6:50 delivering a bite considered the
6:52 strongest in the world with up to 3,700
6:55 lb of force. That's almost four times
6:57 stronger than a lion's bite. But this
6:59 power mainly depends on your size. The
7:01 bigger you are, the more your muscles
7:02 scale up, and strength grows
7:04 accordingly. Without your massive size,
7:06 you couldn't unleash such a devastating
7:08 bite and hold your prey with this kind
7:11 of ease. Still, the real secret lies in
7:13 your teeth. Their long conicle,
7:15 razor-sharp shape evenly distributes the
7:17 crushing force of your bite, keeping
7:18 them from breaking under extreme
7:21 pressure. You've got that zebra in your
7:24 jaws. But now what? Your teeth are just
7:27 hooks, not knives. They're very good at
7:30 catching, but very bad at cutting. You
7:32 can't swallow the whole zebra at once.
7:34 You're not a snake. You're stuck with
7:37 food you can't eat. That's a problem.
7:39 Unless crocodiles already found an
7:41 ingenious solution 200 million years
7:44 ago. Yes, they did. That solution is
7:46 called the death roll. Or in other
7:48 words, your brain's only telling you one
7:50 thing. Spin. More precisely, you first
7:52 fold your legs flat against your body.
7:54 That's inertia in physics. You shrink
7:56 your radius by nearly half and suddenly
7:58 the same effort makes you whirl several
8:01 times faster. First rotation, the water
8:03 churns you as you whip your massive body
8:05 around. water exploding into white foam
8:08 as your body becomes a living drill. But
8:10 it's not enough. The zebra remains
8:13 stubbornly intact. Second rotation, you
8:15 pick up speed. Your body thrashes so
8:17 violently that the water around you
8:20 turns into a storm. Third rotation,
8:21 something inside that zebra makes a
8:23 sound like dropping a watermelon from a
8:25 rooftop. With each rotation, you're
8:27 solving the too big to eat problem with
8:29 pure brute force. Your body generates
8:31 forces strong enough to tear through
8:34 muscle and snap bones. The leg separates
8:35 with a noise that would make a butcher
8:38 request a career change. The water turns
8:40 red. Part of the zebra stays locked in
8:42 your jaws. The rest drifts away in
8:44 pieces. You've just converted a large
8:47 mammal into a very disturbing unboxing
8:49 video. It's not called the death roll
8:52 for nothing, right? Because crocodiles
8:54 can't chew, you have no mers to grind
8:56 meat into smaller pieces. So instead,
8:58 the death roll replaces chewing
9:00 entirely. A few death rolls later, what
9:03 was once a zebra is now perfectly sized
9:05 for swallowing. When your food's too big
9:07 to be swallowed, you spin until it's
9:09 not. Honestly, you chop better than the
9:11 blender in my kitchen. I wish you were
9:14 my blender. Oh, look. A few of your
9:16 teeth popped out during that roll.
9:18 Luckily for you, you've got a built-in
9:20 factory. Throughout your life, your
9:22 teeth are constantly falling out and
9:23 being replaced with new ones. And that
9:25 means you'll always have sharp, gleaming
9:28 teeth. My grandmother would be jealous.
9:30 All right. Now, let's take this meal
9:31 down to the depths where no one can
9:34 disturb you. And by the way, let me
9:35 introduce you to an amazing miracle
9:38 inside your body. Your four-chambered
9:40 heart. It comes with a rare feature
9:42 called the forin of pinea. This valve
9:44 allows you to redirect blood flow
9:46 depending on the situation. Something
9:48 almost no other animal can do. When you
9:49 dive, blood flow to your lungs is
9:51 reduced since you don't need them
9:53 underwater, and instead it's rerouted to
9:55 your brain, heart, and other vital
9:57 organs, the ones that truly need oxygen
10:00 right now. This lets you stay submerged
10:02 for very long periods, sometimes more
10:04 than an hour. Plenty of time to finish
10:06 your feast.
10:10 H as tasty as expected. And while you're
10:11 eating, the same valve directs carbon
10:15 dioxide rich blood to your stomach. Why?
10:16 Because CO2 accelerates the production
10:18 of stomach acid 10 times faster than
10:20 mammals. That means you can digest
10:24 bones, horns, shells, everything.
10:26 Nothing goes to waste. And this single
10:29 meal will fuel you for nearly 3 months.
10:31 That means no hunting for a long while.
10:33 Enough time to finish every Netflix
10:35 series if you wanted. Your life is
10:36 basically a holiday with just four
10:39 working days a year. Now I'm the jealous
10:42 one, not my grandmother. You see, the
10:43 energy you've just gained from this
10:46 feast will be managed wisely. Any other
10:48 animal your size burns 10 times more
10:50 energy than you do simply because
10:52 warm-blooded creatures waste most of it
10:55 on producing body heat. Poor mammals.
10:58 But you, a cold-blooded reptile, have a
11:00 smarter trick. You head to the riverbank
11:03 and bask in the sun. Your dark skin
11:05 absorbs all seven colors of the light
11:06 spectrum, letting you capture solar
11:09 energy with maximum efficiency. This
11:11 way, you warm your body without using
11:13 your own stored energy, saving it for
11:15 serious moments like fighting another
11:17 predator or hunting. After a while,
11:19 you'll start to feel your body heat
11:21 rising more than it should. And that's
11:24 when you'll realize you can't sweat.
11:26 Still, you have clever ways to cool
11:28 down. Either open your mouth to let the
11:30 moisture inside evaporate and lower your
11:32 temperature, or slip back into that
11:34 refreshing water. It depends on your
11:37 mood. Most often you choose the first
11:39 option, opening your mouth, because you
11:41 can even take a nap while doing it. And
11:44 your nap isn't an ordinary nap. You
11:45 close one eye while keeping the other
11:48 open, leaving half of your brain awake,
11:50 alert to any danger, while the other
11:52 half rests peacefully. Your survival
11:54 chances, once just 1% in your early
11:57 years, are now 95%. Thanks to your
11:58 extraordinary abilities and your
12:00 enormous size, it's almost impossible to
12:03 bring you down. And your size gives you
12:05 another great advantage. conserving
12:07 energy far better than smaller crocs.
12:09 That's because body volume grows by the
12:11 cube while surface area only by the
12:13 square. So larger animals lose heat much
12:15 more slowly compared to the tissue they
12:17 hold inside. And that's why giants like
12:19 you dominate, capable of surviving for
12:22 months without food, unlike the smaller
12:24 ones who starve quickly because they
