Name: Basically Every Mammal Is Good at Swimming... Except Us
Uploaded: 2021-05-11T13:11:36.000Z
Duration: 12 min 10 s
Description: VoiceTubeの動画で発音を聞きながら英語表現を覚えよう！学べる英語：

This episode is brought to you by  the Music for Scientists album,

We humans like to think  we're pretty good swimmers.

Most other mammals don't need lessons!  For them, swimming is instinctual.

And that includes the mammals you'd least expect

to be at home in the water… like… moose.

we're talking up to 600 kilos sitting  atop four comically thin legs.

So, you might not think they'd be great swimmers.

But in summer and fall,  they're often found in water.

And they're not just dipping their hooves.

Moose will fully submerge themselves  and paddle up to 20 kilometers.

During this, their heads bob  in and out of the water —

which you might think would  lead to some serious nasal burn.

Luckily for them, their long,  flappy snoots act like a valve

to keep water from getting in their nostrils.

Now, at first, some biologists thought that

these aquatic exploits were a way of cooling off.

After all, that thick fur jacket  they wear is better for keeping cozy

in those minus -30 degree winters  than it is keeping cool in summer.

But then, they realized the animals  had an even better reason to swim.

Studies of their diets revealed that they  pick plants based on how salty they are.

And the plants that have the most  salt — like pondweed and bur-reed —

One moose that researchers  observed even had a nifty trick

for feeding in the shallows: it used its  powerful nose to blow away the water first.

Though, they'll also dive several  meters down, if they have to.

They're so keen on salt because  it's an essential nutrient

And without it, they can't  grow those impressive antlers.

There might also be other reasons  they spend so much time in water,

like avoiding mosquitos.  Or escaping hungry wolves.

But whatever the motivation for  swimming, they sure seem to enjoy it!

Moose aren't the only large  animals who are good at paddling.

Elephants can swim long distances  with a kind of lunging-style,

sticking their trunks out above the  water and using them like snorkels.

Now, at first glance you might think  that elephants are too big to float.

But, it turns out their size actually helps them.

See, objects float because the downward  pressure from the weight of the object

is less than the pressure of the water  pushing upwards. That's buoyancy.

And although elephants are  heavy, they're also wide.

So, their bodies displace enough  water to counteract their weight —

They also have sizable lungs, so swimming  probably doesn't tire them out much.

And all those plants they eat  make gas in their stomachs,

kind of inflating them like a big balloon.

Oh, and their skull bones have lots of  holes in them, kind of like a sponge—

which is probably to make them slightly  less heavy, but it also gives them buoyancy.

Researchers think that  elephants' swimming abilities

might have helped their ancestors  colonize offshore islands.

And fossil evidence shows that  ancient island-dwelling elephants

So swimming could have helped  elephants find new food sources

and reduce competition between individuals.

Nowadays, elephants might swim  to keep their huge bodies cool —

although no one has tested  this idea scientifically yet.

Armadillos look more like living  tanks than agile water-babies.

Still, they're innately  better swimmers than we are.

They'll doggy-paddle their way through  the water, with their ears lying flat,

poking their little noses out  every now and again for air.

Actually, it's kind of a big  part of their whole swim game.

They're naturally negatively  buoyant, meaning they sink in water.

And it seems like they sometimes roll with that,

and just run their way along the  bottom if it's shallow enough.

when a researcher kept throwing into the water.

But for deeper crossings, nine-banded armadillos

have been seen gulping large amounts of air.

And researchers think that's to inflate  their stomach and small intestine

Some of the first observations of  armadillos swimming date back to the 1930s,

where biologists saw that they  could swim about 50 meters

And in 1994, Brazilian fishers  found a female yellow armadillo

swimming along about 50 meters  off the island of Cajual.

The animal might have been making  the 500-meter swim from the mainland

to reach the rich food resources on  the island—things like crabs, tubers,

from the mainland predators  that don't exist there.

The same theory might explain how armadillos  made it from Missouri to Illinois —

by paddling between chunks of land  to cross the Mississippi River.

Right now though, scientists only  have a few observations to go by,

so it's hard to know how or why  armadillos started swimming,

or whether it's a really common behavior.

But they definitely seem to  know how to, if they need to!

In north-western parts of India, you can witness

an unexpected sight: herds of camels swimming.

These are the Kharai — the only  camel breed that regularly swims,

Like moose, they paddle more than 3  kilometers in search of their favorite fare.

In fact, it's been reported that their  name comes from the local word for salty or

saline, since they love eating  salty plants like mangroves.

because locals breed them as  draft animals and for their milk.

But around 2,000 years ago swimming  camels may have been a lot more common.

According to fossil and DNA evidence, it  may have been our domestication efforts

字幕リスト動画再生

Basically Every Mammal Is Good at Swimming... Except Us

instinct

evidence

basically

ancient