mammal

A dolphin is a mammal, even though it lives underwater. ▶

海豚虽然生活在水下，却是哺乳动物。

Protecting marine mammals requires international cooperation because these animals often migrate across the waters of several countries.

保护海洋哺乳动物需要国际合作，因为这些动物经常跨越多个国家的水域迁徙。