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

Two years after mountain gazelles were released in central Arabia, the soci al 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 commo n social groupings were solitary adult males (20% of groups), groups of mal es (13%), solitary adult females (14%), and groups of females and juveniles , either with (14%) or without (27%) an adult male. The companions of a fem ale were determined primarily by her reproductive status. Adult females wer e often alone (18% of individual females), especially around the time of pa rturition, or accompanied by just a juvenile (22%), or just an adult male ( 5%), or both (5%). Sometimes, their companions included one (27% of individ uals) or two (11%), and rarely three or four, other females and their juven iles. 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 (<12 5 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 t han in summer. Differences in total rainfall between years also had no obvi ous effect on social organization, which varied little between 1993 and 199 4, although rainfall during the winters at the start of these years varied five-fold. (C) 1999 Academic Press.