The social organization of mountain gazelles Gazella gazella in a population reintroduced to central Arabia

Abstract

Two years after mountain gazelles were released in central Arabia, the social organization of the reintroduced population was similar to that of wild populations. It was uninfluenced by the captive origins of the population's founders, which are now a minority of the study population. The more common social groupings were solitary adult males (20% of groups), groups of males (13%), solitary adult females (14%), and groups of females and juveniles, either with (14%) or without (27%) an adult male. The companions of a female were determined primarily by her reproductive status. Adult females were often alone (18% of individual females), especially around the time of parturition, or accompanied by just a juvenile (22%), or just an adult male (5%), or both (5%). Sometimes, their companions included one (27% of individuals) or two (11%), and rarely three or four, other females and their juveniles. Some adult males were territorial and they were usually solitary (58% of days) or with females (38% of days). Subadult males and non-territorial adult males formed bachelor groups, which rarely associated with females. The largest group of gazelles comprised 11 males, but more than 72% of all sightings were of solitary gazelles or groups of two. Rainfall was low (<125 mm annually) and seasonal, but runoff accumulated in wadis and was stored in the subsoil. Consequently, food availability for gazelles in the wadis, although low, was less seasonally-variable than rainfall. Territories were maintained throughout the year and there was little seasonal variation in group composition, although female groups were often larger during winter than in summer. Differences in total rainfall between years also had no obvious effect on social organization, which varied little between 1993 and 1994, although rainfall during the winters at the start of these years varied five-fold.