Among vertebrates, the best konow social parasites are such birds as cuckoos and cowbirds;the female lays an egg in a nest belonging to another species and leaves it for the host to rear.

• 脊椎动物中，最有名的寄生生物，如杜鹃、牛鹂，它们的雌鸟在其它鸟的巢中产卵，并靠巢的主人饲养其后代。