The pubertal transition in the play fighting of male rats : developmental byproduct or ontogenetic adaptation?

xii, 137 leaves : ill. ; 28 cm.Playing is a common behavior among juveniles of many mammalian species, including rats (Rattus norvegicus). The mechanisms underlying the change that occurs in the play fighting of male rats at puberty were the focus of this thesis. It was found that castration at weaning disrupted the formation of male-typical dominance relationships, but did not alter the pubertal changes in play fighting, whereas neonatal castration prevented the shift from juvenile- to adult-typical behaviour at puberty. This transistion is male specific and cannot be induced in females by exposing htme to more extreme social contexts, involving interactions with unfamiliar males. The change in play by males at puberty is not, then, a byproduct of other sex differences, but results from a highly specific mechanism in early infancy. The significance of this sex difference is explored with respect to the functions of play fighting in rats and other species