Prehistoric ground sloths first appeared around 35 million years ago.

大约3500万年前， 史前大懒兽开始出现。

Giant ground sloths were 500 times bigger than their modern relatives.

巨型地懒的体型比他们的现代亲戚大500倍。

Some ground sloths, like the megalonychidae, were cat-sized, but many were massive.

一些大懒兽体型和猫一样大， 如二趾树懒，但很多都是体型庞大的。

Others, however, such as giant ground sloths, giant hyenas, and mammoths went extinct.

但是其余的动物，如巨型地懒、巨鬣狗、和猛犸象则灭绝了。

The new human arrivals loved the avocado's flesh as much as the ground sloths did.

新来的人类和地懒一样喜欢牛油果肉。

Although the giant ground sloth is now extinct, like the opossum, it has family ties in South America.

尽管巨型地懒已经灭绝，但是像负鼠一样，南美也能找到它的“家庭成员”。

The die-off in South America included giant ground sloths and armadillo-like animals the size of cars known as glyptodonts.

南美洲灭亡的动物包括大型地懒和一种犰狳科动物，足足有汽车大小的雕齿兽。

It's the claw from a giant ground sloth and it really was a giant—6 metres long and weighing up to 4 tons.

巨型地懒，这种地懒巨大无比，身长6米，体重40多吨。

Some ground sloths, like the megalonychid, were cat-sized, but many were massive.

一些地面树懒， 如巨爪龙，有猫那么大，但很多都很大。

Ground sloths flourished for millions of years, but around 10,000 years ago, they started disappearing along with the Western Hemisphere's other giant mammals.

大懒兽物种繁盛了几百万年，却在一万年前开始灭绝，一同灭绝的还有西半球其他巨型哺乳动物。

Once among the largest animals in South America, giant ground sloths were three to four meters long and usually walked on all four legs.

巨型地栖树懒曾经是南美洲最大的动物之一，有三到四米长，通常用四条腿走路。

I'm talking about Tanque Loma, where at least 22 giant ground sloths in the genus Eremotherium met their end.

我说的是 Tanque Loma，那里至少有 22 只 Eremotherium 属的巨型地懒死亡。

Maybe a bison, or a camel, or a ground sloth.

也许是野牛、骆驼或地懒。

So giant ground sloths enjoying a dip from time to time wouldn't be that strange, from an evolutionary perspective.

因此，从进化的角度来看，巨型地面树懒时不时地享受一下并不奇怪。

From the 90-foot apatosaurus to the giant ground sloth, a diverse range of creatures have prospered, and perished, on our planet.

从 90 英尺长的雷龙到巨大的地懒，各种各样的生物在我们的星球上繁衍生息过，也曾灭亡过。

And it is full of bones - literally thousands of them, most of which belong to that one species of giant ground sloth.

它里面装满了骨头——字面上有数千块，其中大部分属于那种巨型地懒。

One of the earliest ideas was that cats used them to penetrate the armor of Ice Age animals like giant armadillos and ground sloths.

最早的想法之一是猫用它们来穿透冰河时代动物的盔甲，比如巨型犰狳和地懒。

Meanwhile, in South America, there were marsupials, giant ground sloths, and huge cousins of the armadillo called glyptodons that moved north.

与此同时， 在南美洲，有袋类动物、巨型地懒和犰狳的巨大表亲雕齿兽向北迁移。

And it's in this isolation that  unique animals originated -- like giant ground sloths and armored glyptodons, the enormous relatives of today's armadillos.

正是在这种与世隔绝的环境中， 独特的动物诞生了——比如巨型地懒和铠甲雕齿兽，它们是当今犰狳的巨大亲戚。

So if giant ground sloths were social and lived in groups, that expands our understanding of what it means to be a sloth!

因此， 如果巨型地懒是群居的并且群居，那将扩展我们对成为树懒意味着什么的理解！