要论忠诚，美洲鸵肯定不是，因为它们没有固定的配偶。正因如此，雄鸟要独自承担起孵卵、喂食、照顾和保护后代的责任。
　　
　雄鲶鱼——用嘴孵化卵子

　　
　　Catfish（鲶鱼）：A father sea catfish keeps the eggs of his young in his mouth until they are ready to hatch. He will not eat until his young are born, which may take several weeks.
　　鲶鱼大家都熟悉吧？和达尔文蛙相似，雄性鲶鱼也是把雌鲶鱼产的卵含在嘴里，以此孵出小鲶鱼。不同的是，雄鲶鱼在这段时期不能进食。