mammal
 US /ˈmæm.əl/
 UK /ˈmæm.əl/

1. 
哺乳類
a warm-blooded vertebrate animal of a class that is distinguished by the possession of hair or fur, females that secrete milk for the nourishment of the young, and (typically) the birth of live young.
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• 
Humans are mammals.
人間は哺乳類です。
• 
Whales are marine mammals.
クジラは海洋哺乳類です。