Whales fall under the class of mammals.

鲸属于哺乳类动物。

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Even within our own class, mammals, roughly 300 new species have been discovered in the first decade of this century-mostly rodents, but also marsupials, a beaked whale and a slew of primates.

按照我们的分类标准，仅是本世纪的头十年，我们就发现了大约300种哺乳动物新物种——大部分是啮齿类，也有有袋类，突吻鲸类以及大量的灵长类动物。

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The echidna is such a unique animal that it is classified in a special class of mammals known as monotremes, which it shares only with the platypus.

因针鼹鼠之独特，被定类为特殊的哺乳动物，属单孔类动物。单孔类动物只有针鼹鼠和鸭嘴兽。

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