ABSTRACT
The survival and development of newborn mammals depends upon complex coordinated interactions with the mother and, at least in some species, other conspecifics, including the father and siblings. Although neonates cannot live without the resources provided by their mother, they are not simply passive recipients of maternal care. Beginning shortly after birth, mammalian young exhibit species-typical behaviors that contribute to their own wellbeing. Mothers in particular are highly sensitive to signals that communicate the physiological and motivational state of their infants. For example, when removed from their nest, mouse and rat pups emit ultrasonic “distress” cries that attract their mother and thereby enable her to retrieve them (Allin and Banks, 1972; Noirot, 1966; Zippelius and Schleidt, 1956). Isolated lambs bleat, similarily facilitating parent-offspring reunion and nursing (Walser et al., 1984). In a reciprocal manner, adults communicate via various sensory modalities with their newborns, who, in turn, display overt responses to their parents (or cues that they produce) that are critical for survival.
