MAMMAL, n.pl.A family of vertebrate animals whose females in a state of nature suckle their young, but when civilized and enlightened put them out to nurse, or use the bottle .

• 哺乳动物：脊椎动物的一类，其雌性具有用乳房哺喂幼儿的天性，不过，一旦这类动物进入文明社会，它们就会把幼儿交给保姆，或者用奶瓶喂养它们。