GROUP-SIZE, SPATIAL SEGREGATION AND ACTIVITY OF WILD SYMPATRIC VICUNAS VICUGNA-VICUGNA AND GUANACOS LAMA-GUANICOE

Group size, activity and spatial segregation of sympatric guanacos and vicunas have been investigated in the wild in the Catamarca Andes, Ar gentina. A total of 65 groups of vicunas and 32 of guanacos was sighte d. The size of vicuna and guanaco groups (mean +/- SD: 4.8 +/- 4.5 ind ividuals and 3.5 +/- 3.6 individuals respectively) fell within the ran ge reported by other studies. The occurrence of solitary guanacos was unusually high. Spatial overlap between vicunas and guanacos was wide and occurred from 4000 to 4200 m altitude. Possibly, the two species a ttained segregation through the use of areas differing in slope gradie nt. Most guanacos and vicunas were foraging when spotted. The proporti ons of individuals engaged in foraging, resting and walking were, howe ver, different between the two species, the percentage of guanacos gra zing (94%) being particularly high in comparison with vicunas (69%). V icuna activity pattern varied throughout the day. They were on The mov e mainly just after midday and rested mainly late in the afternoon. Gu anaco group size and pattern of activity showed more variations from o ther studies than those of vicuna. These differences may be related to the high altitude, In such an area, which lies at the upper limit of their altitudinal range, guanacos may have problems in meeting their e nergy demands, which an higher than those of vicunas. Competition betw een the two species may occur in sympatric areas.