ABSTRACT
The posterior pituitary hormone oxytocin, which stimulates milk release during suckling, also promotes parenting behaviour in various species. Levels of circulating hormones vary dramatically during pregnancy. Experimental studies in rats have shown that these changes are related to aspects of maternal behavior. Mothers will also respond to specific calls emitted by pups which indicate that the pups are cold or hungry. The fact that these maternal responses follow pregnancy suggests that hormonal changes sensitize maternal behavior. The mother's care not only involves providing nutrition, but also uses species-typical behaviors that assist maintenance of the infant's body temperature, and stimulation of the development of important functions such as standing and locomotion, defecation and passing of urine. Administration of prolactin also stimulates nest building. The posterior pituitary hormone oxytocin, which stimulates milk release during suckling, also promotes parenting behavior in various species. However, the hormone effects are small compared with parental learning and environment.
