B2 中上級 1945 タグ追加 保存
動画の字幕をクリックしてすぐ単語の意味を調べられます!
単語帳読み込み中…
字幕の修正報告
If there's one thing you know about sloths, it's that they're, well, slow.
But that doesn't mean they're boring.
In fact, sloths are one of the most extreme animals on the planet, and not just because they poop only once a week.
First of all, sloths really are extremely slow.
Their top speeds clock in at just 0.25 kph, making them the slowest mammal on the planet.
According to zoologist Becky Cliffe, that's because, well, sloths can't really see.
60 million years ago, they lost the ability to see.
They went almost completely blind.
So, in the daytime, a sloth actually can't see anything cause it's too bright.
If you can't see where you're going, you can't run around because you're going to fall out of the tree.
Moving slowly may sound like a liability, especially if you're nearly blind, but being sluggish actually comes with all kinds of benefits.
For one, they save an enormous amount of energy.
In fact, sloths use about 90% less energy than the average mammal, which is vital, considering their diet is a low-energy snack consisting of leaves...with a side of leaves.
And as it turns out, being slow also helps sloths avoid detection.
You see, sloths are so slow that predators like jaguars and eagles, which use movement to hunt, can't even find them.
But some sloths take predator avoidance to the next level.
Thanks to rare extra vertebrae in its neck, the three-fingered sloth can turn its head 270 degrees, which allows it to smell incoming predators from almost any direction, and that's especially useful when you spend nearly all of your time motionless in a tree.
In fact, sloths sleep, mate, and even give birth all while hanging upside down on a branch.
And, as you might expect, that requires some pretty extreme adaptations.
They've got special tendons in their hands, which lock into place.
And, along with their long, hooklike fingernails, allow them to hang easily.
They're like a giant coat hanger.
And to combat a rush of blood to the head, which might be familiar if you've ever hung upside down...
They have special sort of valves in their circulatory system that does actually stop the pooling of blood in the head.
But if you think that's extreme, consider this: once a week, sloths risk their lives on a daring journey from the protective forest canopy to the ground.
Their mission?
To poop.
And it really is risky.
We suspect about 60% of predator-based sloth deaths happen while they're pooping.
They literally risk their life to come down to the ground.
So they have to make it count.
And, boy, they really do.
Sloths can lose an astonishing 30% of their body weight each time they go.
Plus, they might get a mate out of it.
How do you find a mate if you're solitary and you can't move very far?
Well, they're gonna have to use pheromones and scent markers.
I think that coming down and leaving a little pile at the base of your favorite trees is sort of like a little signpost.
But if there's one thing that really pushes sloths over the top, it's their rough fur.
Sloth fur has its very own ecosystem.
Because they live in the rainforest, it's often wet, which creates the perfect environment for algae to grow and provide sloths with green camouflage.
But it isn't just algae that calls a sloth's fur home.
You can also find beetles, cockroaches, and a species of moth that's found nowhere else in the world except for on a sloth.
And the sloths don't seem to mind one bit.
But that's not all.
Their fur might actually save lives.
Fungi in their fur have been shown to fight breast cancer cells, and they may also have properties for fighting malaria.
So, despite their slow pace, sloths are far from boring, and in some environments, they aren't even slow.
I mean, look at that daredevil go.
コツ:単語をクリックしてすぐ意味を調べられます!

読み込み中…

読み込み中…

可愛すぎる!ナマケモノのまったり生態に迫る (The Extreme Life Of A Sloth)

1945 タグ追加 保存
Helena 2019 年 12 月 17 日 に公開    newzealand 翻訳    Sophie チェック
お勧め動画
  1. 1. クリック一つで単語を検索

    右側のスプリクトの単語をクリックするだけで即座に意味が検索できます。

  2. 2. リピート機能

    クリックするだけで同じフレーズを何回もリピート可能!

  3. 3. ショートカット

    キーボードショートカットを使うことによって勉強の効率を上げることが出来ます。

  4. 4. 字幕の表示/非表示

    日・英のボタンをクリックすることで自由に字幕のオンオフを切り替えられます。

  5. 5. 動画をブログ等でシェア

    コードを貼り付けてVoiceTubeの動画再生プレーヤーをブログ等でシェアすることが出来ます!

  6. 6. 全画面再生

    左側の矢印をクリックすることで全画面で再生できるようになります。

  1. クイズ付き動画

    リスニングクイズに挑戦!

  1. クリックしてメモを表示

  1. UrbanDictionary 俚語字典整合查詢。一般字典查詢不到你滿意的解譯,不妨使用「俚語字典」,或許會讓你有滿意的答案喔