The name monotreme means one hole referring to the single orifice they use for reproduction, excretion, and egg-laying.

单目这个词一个，是一个用于生育、排泄，和下蛋。

And these ancient egg-layers probably reproduced a lot like today's monotremes do.

这些古老卵层可能像今天单类一样繁殖。

As a monotreme, she's part of the most ancient lineage of mammals alive today.

作为单类动，她是当今最古老哺乳动谱系一部分。

The three modern mammal groups -- the placentals, marsupials and monotremes -- all made it.

三个现代哺乳动群——盘 动、有袋动和单动——都成功了。

There were once hundreds of monotreme species, but there are only five left: four species of echidnas and the duck-billed platypus.

曾经有好几百种单目哺乳动，现在仅存5种：4种针鼹和鸭嘴兽。

And we think monotremes have been doing it more or less that way this whole time.

我们认为单类动一直以来或多或少都是这样做。

Well, there's the platypus, an egg-laying monotreme with venomous spurs.

嗯，有鸭嘴兽，一种产卵单动，有毒刺。

Another idea is that therians followed a path similar to the monotremes, where eggs were retained in the mother's body for longer and longer periods of time.

另一个想法是， therians 遵循类似于单类动路径，卵子在母亲体内保留时间越来越长。

For crown group mammals, our most recent common ancestor is the one shared by placentals like us, marsupials like the kangaroo, and the monotremes like the platypus.

对于冠群哺乳动，我们最近共同祖先是像我们这样盘动、袋鼠这样有袋动和鸭嘴兽这样单类动共有祖先。

These little creatures didn't belong to any of the three main mammal groups on the planet today—which are the placental mammals (like us), monotremes (like the platypus) and marsupials (like koalas and kangaroos).

这些小动不属于当今地球上三个主要哺乳动群中任何一个——盘哺乳动（如我们）、单类动（如鸭嘴兽）和有袋动（如考拉和袋鼠）。

These subtle creatures didn't belong to any of the three main mammal groups on the planet today-which are the placental mammals (like us), monotremes (like the platypus) and marsupials (like koalas and kangaroos).

这些小动不属于今天地球上三个主要哺乳动群体——盘哺乳动(像我们)、单目哺乳动(像鸭嘴兽)和有袋哺乳动(像考拉和袋鼠)。

The playtpus belongs to an unusual group called monotremes that diverged from the branch of the mammal family tree that leads to marsupials -- and later placentals -- around 186 million years ago.

playtpus 属于一个不寻常类群，称为单类动，大约在 1.86 亿年前，它从导致有袋类动和后来盘类动哺乳动家族树分支中分离出来。

Reptiles, amphibians, most birds, and monotremes like the platypus have a cloaca, a multipurpose swiss army knife of holes, linking the urinary, waste, and reproductive systems… I guess you could say: one ring to rule them all.

爬行动、两栖动、大多数鸟类和像鸭嘴兽这样单类动都有泄殖腔，这是一把多用途瑞士军刀，连接着泌尿系统、废系统和生殖系统… … 我想你可以说：一环统领它们。