00:00Lions, dogs, cats, all these mammals sleep in pretty comfortable positions, but not whales.
00:06They look like giant floating loaves of bread, which is a scene one diver accidentally came across in the Caribbean Sea.
00:13Six whales were just standing upright with their tails pointed down at a depth of about 65 feet below the surface.
00:21Scientists discovered that when sperm whales take a nap, they stay in this position for 10 to 15 minutes.
00:27They don't move or breathe, but these creatures spend only 7% of their time asleep, far less than other mammals.
00:35Usually, they either rest peacefully in the water or relax, slowly swimming next to other marine animals.
00:42When they're moving and sleeping at the same time, they're actually taking a nap.
00:46These animals can't go too deep and need to stay close to the surface.
00:50Great white sharks sleep and hunt at greater depths, which means one less thing to worry about when taking a quick nap.
00:57Plus, it gets pretty cold the deeper you go, and whales need warmer environments that can help them maintain the temperature of their large bodies.
01:06When alone, dolphins enter a stage of deep sleep.
01:10It usually happens at night and lasts for only a few hours at a time.
01:14While sleeping, the animal floats at the surface.
01:17It shuts down half of its brain, I can relate, together with the opposite eye.
01:22The other half is at a low alert level, awake and ready to react if some unwanted visitor comes closer.
01:29The part of the brain that is awake also sends signals when it's time to go up to the surface to take a breath of fresh air.
01:37Marine mammals have the blowhole.
01:39That's a flap of skin they can open and close whenever they want.
01:42People breathe automatically.
01:45Your body knows what it needs to do even when you're sleeping.
01:48But whales and dolphins have a voluntary breathing system.
01:52It means they need to consciously go to the surface to get some air.
01:56And one part of their brain needs to always be awake to inform the animal it's time to go up.
02:02Whales and dolphins can hold their breath way longer than other species.
02:06They also have a higher tolerance for carbon dioxide and can take in more air.
02:11Their red blood cells store more oxygen, too.
02:15Whales and dolphins' blood goes only to those body parts that really need oxygen.
02:20If a whale only uses its brain, heart, fins, and some other muscles needed for swimming at the moment,
02:26those will also be the only body parts that will get the oxygen.
02:30Digestion or other functions can wait.
02:33The ocean is not a place where you can relax and peacefully fall asleep.
02:36While sleeping, fish reduce their activity.
02:40Their metabolism becomes slow.
02:42Some of them keep floating in the same spot.
02:45Others find a safer place among corals or in the mud.
02:49Early in life, dolphins learn to make a unique whistle that helps others from their pod to identify them.
02:55That means these specific whistles are their names, and dolphins do respond to them.
03:00Clams have feet.
03:03It looks like a large tongue that sometimes protrudes from the shell.
03:06But that's actually the foot.
03:09And it's relatively long compared to the length of the animal.
03:12Clams use this limb to dig themselves in the sand.
03:16The blue whale is the largest living animal.
03:19And it's also larger than the majority of dinosaurs used to be.
03:22They can grow to more than 100 feet long and have a weight of almost 200 tons.
03:28That's like 50 adult elephants.
03:30A blue whale's tongue alone can weigh more than one elephant.
03:34Such a giant surely needs to eat a lot.
03:36Half a million calories in just one mouthful.
03:40The blue whale's heart is the size of a small car and weighs 1,300 pounds.
03:45To move the blood through such a giant body, the heartbeats are so strong, you can hear them even from 2 miles away.
03:53The heart of a whale beats only 8 to 10 times per minute.
03:57The whale is one of the loudest creatures out there.
03:59Its call can go up to 180 decibels, which is as loud as a jet plane.
04:05Almost 95% of jellyfish's body is made of water.
04:09For comparison, the human body is 60% water.
04:12It's probably not a surprise since jellyfish don't have a heart, blood, eyes, or brain.
04:19The other 5% of their body weight is proteins, muscles, and nerve cells.
04:24Jellyfish have been around for more than 500 million years.
04:28This makes them older than dinosaurs.
04:30These creatures haven't changed much, and today's jellyfish are pretty much like their ancestors.
04:35These creatures live in the ocean, but in 1991, more than 2,000 jellyfish polyps were taken into space.
04:44Scientists wanted to see how they would react in the environment with no gravity.
04:48The jellyfish reproduced and created 60,000 new polyps.
04:53But unfortunately, those couldn't function normally after getting back to Earth.
04:57One species of jellyfish can literally live forever.
05:01As it grows older, the critter goes down to the seafloor to become a polyp again.
05:06And that polyp turns into a new jellyfish with the same genetics.
05:11Greenland sharks can live 500 years.
05:14This is an animal with almost the longest lifespan among vertebrates.
05:19Sperm whales are sociable creatures.
05:21They spend their life surrounded by their family.
05:23These animals support one another and have close friends they remember well,
05:28even if they don't see each other for a long time.
05:32Electric eels have small eyes that are not so effective in environments with no light,
05:37so they mostly rely on their electric organs.
05:40Those consist of 6,000 cells.
05:43Eels use them to stow power, similar to batteries.
05:46These creatures use electricity, like bats use their radars or dolphins their sonar.
05:51An eel can also produce enough electricity to power a panel of light bulbs.
05:57There's a small tropical archer fish that can learn to recognize human faces.
06:03This fish has an interesting ability to spit small jets of water from its mouth.
06:08Researchers showed the fish the image of two different faces placed side by side.
06:13One was unknown, and the other was familiar.
06:16The fish was supposed to spit water at the familiar one.
06:19The creature took the right guess more than 80% of the time.
06:24Every year in the winter, great white sharks that live along the California coastline disappear.
06:30It feels as if they take a vacation for 30 to 40 days.
06:33The animals go to a point halfway between Hawaii and Mexico.
06:38They might do it to get some food, relax, or hang out with their buddies from other areas.
06:43The spot is now called the whale shark cafe.
06:46Some types of sharks, like makos, whale sharks, or white sharks, breathe in a very specific way.
06:53It requires them to swim all the time.
06:56They also need to move quickly and with their mouth open.
06:59This way, the oxygen can enter and reach their gills.
07:03Sea sponges are some of the most primitive animals.
07:06They're immobile, don't have a mouth, eyes, bones, brain, heart, lungs, or any other organ whatsoever.
07:12And still, they're alive.
07:15There's such a thing as a sea unicorn.
07:18That's an animal called the narwhal.
07:20Its horn is actually a tooth that can grow up to 10 feet long.
07:24Manatees, also known as sea cows, are distant relatives of elephants.
07:29Their weight can go up to 1,000 pounds.
07:32These creatures are vegetarian and need to eat around 10% of their total weight on a daily basis.
07:38That's lots of sea salad.
07:39In some cases, manatees share space with alligators, but they get along pretty well.
07:46You can even find a photo from Florida where an alligator rides a manatee's back.
07:52Frogfish have special fins that help these creatures walk along the sand.
07:57They're very useful in shallow waters.
08:00A ghost pipefish is hard to see, but once you spot it, you're bound to get really surprised.
08:06Its head makes up over 40% of its body.
08:10Crabs don't feel like wasting time on such formalities as putting foods in their mouth.
08:15That's why they taste it with their feet, which is where their taste buds are.
08:20Marine iguanas are the only lizards on our planet that like spending time in the ocean,
08:25even though they mainly live on land.
08:27They're herbivores that feed in shallow waters and swim like snakes.
08:31Iguanas use their long claws to hold on to the bottom when they need to graze.
08:36Green turtles can cross over 1,400 miles when migrated.
08:41They try to find the perfect spot to lay their eggs.
08:44Penguins sort of fly when they're underwater, reaching a speed of 25 miles per hour.
08:50More than 5 million years ago, I've heard – I wasn't around then – deep sea worms and humans had a common ancestor.
08:58So we still share 70% of our genes with these creatures, and with sea stars, squid, and octopuses.
09:06The ocean covers over 70% of our planet, and over 80% of it is unexplored.
09:13More than 1 million species live there.
09:15But there are not only animals.
09:173 million shipwrecks are lying all over the ocean floor, hiding mysterious stories.
09:22Many of them are yet to be discovered.
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