ABSTRACT
The kinds of care provided change over the course of the cycle, because both parent and young are changing physically and behaviorally as a result of their relationship. Granted that caregiving behavior is the resultant of an interaction between parent and offspring, this chapter focuses upon the role that the young play in determining the nature and timing of the care they receive. Current evidence suggests that mammalian young begin to influence their mothers from the earliest stages of pregnancy. In some species, such as mice and dogs, adults are responsive to the young regardless of gender or reproductive condition. A general rule among animals giving birth to several young is that the larger the litter, the shorter the gestation time. Clinical data suggest that the hormones produced by the human fetus also play an important role in initiating the birth process and recent research on the hormones produced by the fetal pituitary promises to illuminate the mechanisms involved.
