Sexual segregation in goitered gazelles (Gazella subgutturosa)

Abstract

Sexual segregation (by habitat or socially) is found in many species, and is especially well described for gregarious ruminants, particularly Cervinae and Caprinae, while less is known about Antilopinae. In this study, we investigated the degree of sexual segregation and social organization of goitered gazelles ( Gazella subgutturosa (Güldenstädt, 1780)), which have a quite distinctive (up to 30%) body size dimorphism between sexes. We used three indices for measuring the degree of sexual segregation: proportion of mixed-sex groups among all groups, proportion of adult females and males in mixed-sex compared with unisex groups, and Conradt’s segregation coefficient (SC). All these measures confirmed that goitered gazelles had very high levels of segregation all year: the proportion of mixed-sex groups was very low (4.6%) compared with unisex herds (95.4%); the proportion of adult males and females in mixed-sex groups was also low (<13%) compared with those in unisex groups; and the SC was very high (0.80–0.98), indicating that considerable segregation occurred. Although SC decreased to some extent during the rut (November–December), as expected, female groups stayed segregated from males (SC = 0.81–0.86) and formed mixed-sex herds only for very short time periods during mating. Surprisingly, the SC dropped to its lowest values during spring (April) and autumn (October) migration periods (0.71 and 0.67, respectively). Our results will contribute to better understanding the behavioural adaptations of goitered gazelle to the arid environment and help in the species conservation and management.