The transition from filial to reproductive function of "Coitus-Related" responses in young guinea pigs

A lordosis‐like response and a purring vocalization which was similar to that emitted by the adult male in precopulatory displays were observed in suckling guinea pigs. During that period in which parental stimulation was required to elicit micturition, both responses occurred in the context of nursing behavior and were frequently followed by the mother's licking the pups' anogenital regions; there was no sex difference in the display of these behaviors. When adult micturition behavior matured, the frequency of lordosing waned in both sexes; purring also declined in females, but in males, purring became associated with a hip‐swaying movement and increased in frequency. In adult females, the display of lordosis and/or purring was confined to estrous periods; males were not observed to lordose as adults, but purred when exposed to estrous females. Isolation‐ and mother‐reared animals displayed the same response organizations in infancy and adulthood. The functional reorganization of these responses in ontogeny is discussed.