Aggression decreases as play emerges in infant spotted hyaenas: Preparation for joining the clan

The early social development of spotted hyaenas, Crocuta crocuta, is marked by a dramatic transition at 2-3 weeks of age, when infants are taken from the isolation of their natal den, where they are intensely aggressive, to the communal den, where they meet most clan members for the first time. This study examined behaviour patterns in eight sets of captive twins during the first month of life to document the changes that prepare young hyaenas for social integration at the communal den. Bite shakes, the most extreme aggressive behaviour, declined markedly within the first week of life, but other forms of aggression remained constant. During week 1, low- intensity prosocial behaviour occurred primarily between mother and cub. By week 2, higher-intensity social play emerged, occurring mainly between siblings. In weeks 3 and 4, cub interactive play was most frequent, lasted longer and was more vigorous. Locomotor and object play did not emerge until weeks 3 and 4, respectively. Dominance relations between siblings were operationally defined by submissive withdrawals. Accordingly, aggression was unidirectional, with dominants initiating most interactions. By contrast, play was reciprocal and equally initiated by dominant and subordinate cubs. Maternal interruption of cub behaviour mainly occurred during extreme aggressive interactions, but rarely during vigorous play. Results showed that prosocial behaviour emerged in captive hyaena cubs following a decline in severe aggression and before the time wild cubs are taken from the natal to the communal den. It is suggested that play may modulate aggression, following the establishment of a dominance relationship, and may serve an immediate prosocial function to prepare aggressive infant hyaenas for integration into the clan.

Duke Scholars

Author Christine M. Drea Evolutionary Anthropology