Comparative Aspects of Behavioural Development in Two Species of Free-Living Hyrax

Abstract

AbstractFour measures of play behaviour of two species of sympatrically living hyrax Heterohyrax brucei and Procavia johnstoni, were studied on three rocky outcrops or kopjes in the Serengeti National Park, Tanzania. The amount of play shown by young of both species, born in 1981, declined during the study. Procavia played at a significantly higher rate than did Heterohyrax throughout this period. This was true even after differences in species' activity were taken into account. Procavia did not show higher rates of behaviour because they had more conspecifics with which to interact. The young of both species of hyrax played with members of the other species; Procavia significantly more so than Heterohyrax. The high rates of interspecific play in Procavia could be explained by their relatively low numbers compared to Heterohyrax on one kopje, but on the other two kopjes they appeared to actively seek out interactions with Heterohyrax. Interspecific differences in the behaviour of young of the two hyrax species were then related to interspecific differences in their adult behaviour. Adult Procavia exhibited higher scores than adult Heterohyrax on three measures of behaviour, reflecting corresponding differences in the play of the young of these species. These differences were found even when adult behavioural scores had been standardised for activity. Furthermore, adult Procavia showed more interspecific behaviour than adult Heterohyrax; a result similar to that found in the play of the young of the two species of hyrax.