Social organization and space use patterns of sexually size dimorphic
Nubian ibex (Capra ibex nubiana) were studied for 26 months in the nor
thern Negev Desert, Israel. The main social units were: female/kid gro
ups that also contained young males up to 3-years-old, immature male (
PG-years-old), mature male (more than 6-years-old), and mixed groups.
Mature males and females were in separate groups except during rut, wh
en mature males moved into areas occupied by females and were equally
likely to be seen in female/kid, mature male, or mixed groups. Outside
the rut, 89% of female sightings were in 4 ha quadrats in which no ma
ture males were seen, but there was a dramatic increase in spatial ove
rlap of adult males and females during the rut as the males moved into
the same areas as females. Young males were found almost exclusively
in female/kid groups (>90% of observations), but as body size of growi
ng males surpassed that of females, they were more frequently associat
ed with other groups. The pattern of sexual segregation of groups and
space, and the age at which males left groups dominated by females and
kids, is consistent with a nutritional hypothesis of foraging pattern
s and social organization for sexually dimorphic herbivores. (C) 1995
Academic Press Limited