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Why don't elephants have pointy ears? - Video học tiếng Anh
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Why don't elephants have pointy ears?
Why don't elephants have pointy ears?
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उपशीर्षक (52)
0:00
- Let's be honest, elephants are pretty silly looking.
0:02
I mean, just look at 'em.
0:04
But one of the weirdest things is
0:06
that they have floppy ears.
0:08
Let me explain. I want you
0:09
to picture every floppy eared animal that you can,
0:12
except for elephants.
0:13
They're all domesticated animals.
0:15
Seriously, try to name another wild animal with floppy ears.
0:19
What's up with that? By default,
0:21
wild animal's ears are mostly pointy-uppy.
0:23
Rigid pointy ears can move around like little sound dishes
0:26
to figure out what direction sounds are coming from.
0:28
So you know you don't get eaten
0:30
or so that you can eat somebody who doesn't hear you coming.
0:33
And stiff ears stay cleaner from things like bacteria.
0:36
Plus then they don't droop over your ear hole,
0:38
which seems like a plus if you have friends
0:39
who want ear snacks.
0:41
But floppy ears do show up in domesticated animals,
0:44
it's most likely a side effect of breeding for tameness.
0:47
Some scientists think that by breeding animals
0:49
that have lower levels of some stress hormones,
0:51
we also accidentally turn down the volume on cells
0:55
that build ear cartilage.
0:56
Because these cells are calmed down.
0:58
They can't produce enough of the chemicals
1:00
that make the ears all pointy uppy causing them
1:02
to accidentally flop over.
1:04
But out in the wild nature has decided that the perks
1:06
of stiff ears outweigh being cute,
1:09
and it's done away with all the floppy ears.
1:11
Except for these... Elephants don't have many predators
1:14
because, well, they're huge.
1:16
Elephants use their big ears for hearing
1:19
and climate control.
1:20
See, elephants generate tons of heat just standing there,
1:23
and they live in some of the hottest places on Earth.
1:26
Staying cool? It's pretty crucial when you've got a
1:27
body like this.
1:29
I mean, elephants don't sweat. They don't pant like dogs.
1:32
That would be weird. Instead to get rid of heat,
1:34
they flap their ears.
1:36
And this works 'cause they have lots
1:37
of large blood vessels in their ears.
1:38
And heat from the blood can escape through the skin.
1:41
They can also squeeze or open those blood vessels in their
1:43
ears to control the amount of heat they give off.
1:45
It's not nature's most popular go-to cooling method,
1:48
but hey, I guess even evolution isn't gonna argue
1:50
with something this big.
1:52
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