哺乳动物起源于25亿年前广泛分布于古超大陆的近似哺乳类的爬行动物。高等哺乳动物的前脑已经进化为包含了三条神经中枢集合的三位一体结构,从解剖学和化学上来看,这些集合反映了一种同早期和晚期爬行动物原始的联系。在由爬行类到哺乳类的进化过程中,三个发展的关键是:(1)同母亲的关怀相结合的保育护理;(2)用于维持母方后代联系的视听信息;(3)活动。“脱离母体的哭声”或许是哺乳动物最早 Mammals originated in approximately mammalian reptiles widely distributed in ancient supercontinent 2.5 billion years ago. The higher mammalian forebrain has evolved into a triad of three central nerve aggregates that, anatomically and chemically, reflect a primitive association with early and late reptiles. The key to the three developments in the evolution from reptiles to mammals are: (1) care and nurse care combined with mother’s care; (2) audiovisual information used to maintain contact with offspring of mothers; and (3) activities. The cry from mother may be the earliest mammal