Seasonal changes in the sexual segregation patterns of Marco Polo sheep in Taxkorgan Nature Reserve

Sexual segregation is observed widely among ruminants, but remains poorly understood in argali. Since sexual segregation is affected by habitat, and in different environments may differ among species and subspecies, we studied this behavioral pattern in Marco Polo sheep (Ovis ammon polii) in their natural habitat at high elevations of the Pamir Plateau using three distinct measurements. We found that, similar to other wild sheep, female and male Marco Polo sheep were highly segregated most of the year and gathered into mixed-sex groups mostly during the rut, which occurred later and for a shorter time than in other argali subspecies experiencing milder climates. This phenomenon was related to the severe environmental conditions of the Pamir Plateau that provided a very short period of favorable weather for birthing and rearing young; correspondingly, aggregation into mixed-sex groups during the rut also occurred later and for a shorter period of time than in other argali populations at lower elevations. Moreover, the degree of segregation between females and males increased with the males’ age. Subadult males switched between male and female groups, staying more with males during lambing and with females during the rut. The timing and duration of sexual segregation and aggregation of Marco Polo sheep were a result of adaption to their local environment.