mammal
/ˈmæməl/noun
- 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哺乳动物。
The first small mammals evolved from reptiles about 200 million years ago, and the group diversified rapidly after the extinction of the dinosaurs to become the dominant form of land animal, with around 4, 000 living species. Mammals belong to the class Mammalia, which contains the subclass Prototheria (monotremes) and the infraclasses Metatheria (marsupials) and Eutheria （placental mammals such as rodents, cats, whales, bats, and humans）.
派生词
mammalian
adjective词源
early 19th cent.: Anglicized form (first used in the plural) of modern Latin mammalia, neuter plural of Latin mammalis (adjective)， from mamma 'breast' （see MAMMA2）.