Interactions and associations between age and sex classes in mouflon sheep (Ovis gmelini) during winter

The fact that sexual segregation can occur in wild ruminants independently of sex-related differences in habitat use suggests that it results at least partly from social mechanisms. One of the simplest mechanisms which can be hypothesised is that individuals avoid the congener classes which frequently try to interact with them (be these interactions 'agonistic' or 'sexual', since courtship behaviour components typically induce withdrawal when performed outside the rut). The aim of the present study was to test, in mouflon sheep (Ovis gmelini), whether the age-sex classes which exchange frequent interactions on meeting occur rarely inside the same groups. Observations were made during winter, on a small population in Germany. Interactions were recorded at an attractive site where all age-sex classes met daily. Foot transects were conducted in parallel over the whole study area in order to determine group composition. As expected, adults of different sexes exchanged frequent interactions at the attractive site and were rarely found in the same groups under free-ranging conditions, while adult females, who interacted little with one another, were quite frequently associated. However, adult males simultaneously exhibited the highest rate of interaction at the attractive site and the highest frequency of association under free-ranging conditions. Unlike female-female and male-female pairs, in which interactions with a clear initiator and a clear recipient predominated, male-male pairs exchanged often spectacular but 'symmetrical' interactions (during which the two individuals behaved in the same way). The hypothesis that sexual segregation results from the avoidance of the congener classes which frequently engage interactions only holds for females. Adult rams interact frequently and seek companions with whom symmetrical interactions can be performed.