Social ontogeny and behavioural diversity: consequences for Bighorn sheep Oris canadensis inhabiting desert and mountain environments

The development of social behaviour was studied in three natural populations of Bighorn sheep ( Ovis canadensis ). Individuals in all populations exhibited the same behavioural repertoires, but the utilization of specific behaviours among both infants and adults differed between populations. It was suggested that differences in the adult utilization of behaviour patterns result in part from behaviours used during infancy. In turn, the social and physical environments affected the development of subsequent behaviour patterns in sheep older than lambs. Desert sheep (in southern California) used mounting behaviours often, presumably because they matured sexually at an early age. Sheep in a more northern environment (British Columbia) used different behaviour patterns more frequently perhaps as a consequence of interactions experienced in larger bands. Additionally, playful interactions were reduced due to physical hazards in the desert, but they were at least nine times as frequent in the northern study population. Play in large groups resulted in the utilization of more different kinds of behaviour patterns. These behavioural findings are interpreted ecologically as consequences of inhabiting environments that differ socially and physically.