SPATIAL-ORGANIZATION IN THE ETHIOPIAN WOLF CANIS-SIMENSIS - LARGE PACKS AND SMALL STABLE HOME RANGES

The spatial organization of the rare Ethiopian wolf (Canis simensis) w as studied in the Afroalpine heathlands of Bale Mountains National Par k, southern Ethiopia, between 1988 and 1992. Nineteen animals were rad io-tracked, 48 ear-tagged and 64 others recognized by coat patterns an d observed directly. Dry season (October-March) home ranges of residen t wolves covered between 2 and 15 km(2). The ranges of adult males wer e slightly larger than those of females, and subadults' home ranges we re slightly smaller than those of adults. The population density of th e wolves was correlated with prey biomass. In optimal habitat, wolves lived in packs of 3-13 adults (mean 5.9 wolves >1 year old) containing several close-kin males; adult sex ratio favoured males 1.88:1 and co mbined pack home ranges averaged 6.0 km(2). In an area of lower prey p roductivity, wolves lived in pairs or small groups (mean 2.7), adult s ex ratio was 1:1 and home ranges averaged 13.4 km(2). Home ranges over lapped extensively (mean 85%) between members of the same pack. Four t o seven percent of the population was additionally composed of non-res ident females, inhabiting larger ranges (mean 11.1 km(2)). Home ranges of neighbouring packs were largely discrete, forming a tessellating m osaic of packs occupying all available habitat. Pack home ranges were stable in time, drifting only during major pack readjustment after the disappearance of a pack or significant demographic changes. Ethiopian wolf home ranges were smaller than would be expected for a carnivore of its size and sociality, presumably as a result of the high rodent p roductivity of the Afroalpine ecosystem.