No mammal except man has more abundant cerebral matter.

任何类都没有这样丰富脑髓神经。

Mammals are the group of animals that humans belong to!

人类属于类动物！

The percentages are very different for different groups of mammals.

不同类动物群体比例差异也很大。

The last group of animals we are going to talk about is mammals.

我们将要后一群动物是类。

But some scientists think mammals also have this capability.

但有些科学家认为类动物也有这种能力。

And as they get older they transition to feeding more on mammals.

当它们越来越大，就要转为喂它们多类。

We see similar hygiene-driven responses in some colony-living mammals.

在一些群居生活类动物身上也会看到出于卫生反应。

In most mammals, the placenta is confined behind a barrier of maternal cells.

大多类动物胎盘 被母亲体内一层细胞屏障围着。

If we hunted all of the world’s wild mammals and birds they’d get us by for a few days.

猎食所有野生类和鸟类，可以再多几天。

Because mammalian predators that stay below that number can exist on prey smaller than them.

因为体重在20公斤以下类动物能以追捕体型小猎物为生。

Most mammals live on land but some such as whales and dolphins live in water.

大多类动物生活在陆地上，例如鲸和海豚生活在水中。

In come amphibians, reptiles, dinosaurs and finally, mammals.

接下来就是会出现两栖动物，爬行动物，恐龙，后是类动物。

It's a tree-dwelling mammal about the size of a raccoon that's native to Southeast Asia.

这种产于东南亚地区在树上生活类动物，体型和浣熊相当。

Killing mammals was either just collateral damage or a form of protection against possible predators.

杀死类动物要么只是一种附带损伤，要么是一种防御潜在捕食者形式。

Like birds, mammals are warm-blooded and breathe air.

和鸟类一样，类是恒温动物，呼吸空气。

You find it associated with play, and all mammals play.

你会发现笑是在玩耍中发生， 而所有类动物都会玩耍。

The small mammals and the larger mammals just can't survive for that length of time on inundated islands.

大型或小型类都不能在淹没岛上生存那么长时间。

In fact, the short-faced bear is probably the largest and most powerful mammalian carnivore that we have.

其实，短面熊有可能是有史以来大、有力类食肉动物。

They are mammals, which means they are warm-blooded, they have fur, and they feed their babies milk.

它们是温血类动物，长颈鹿表面有毛，用母喂养幼崽。

Small mammals are such an important part of the ecosystem for transporting seeds into different areas.

小型类是生态系统中重要一环，它们能把种子送往不同地方。