Small Ruminant Research ELSEVIER Small Ruminant Research 20 (1996) 193-198 Group size, spatial segregation and activity of wild sympatric vicufias Vicugna vicugna and guanacos Lama guaniciie M. Lucherini * Dqx~rmrrnr ofEuo/utionury Biology. Ethology und Br/ruuiourul Ecology Group. Uniurrsity of’Sirnu. Via Murrioii 4. 53100 Sims. ltoly Accepted 18 September 1995 Abstract Group size, activity and spatial segregation of sympatric guanacos and vicuiias have been investigated in the wild in the Catamarca Andes, Argentina. A total of 65 groups of vicuiias and 32 of guanacos was sighted. The size of vicuiia and guanaco groups (mean + SD: 4.8 k 4.5 individuals and 3.5 + 3.6 individuals respectively) fell within the range 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 attained segregation through the use of areas differing in slope gradient. Most guanacos and vicuiias were foraging when spotted. The proportions of individuals engaged in foraging, resting and walking were, however, different between the two species, the percentage of guanacos grazing (94%) being particularly high in comparison with vicuiias (69%). Vicuiia activity pattern varied throughout the day. They were on the move mainly just after midday and rested mainly late in the afternoon. Guanaco group size and pattern of activity showed more variations from other studies than those of vicufia. 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 energy demands, which are higher than those of vicufias. Competition between the two species may occur in sympatric areas. Resumen Este trabajo describe el tamafio de 10s grupos, la segregacidn de espacio y la actividad de vicuiias y guanacos en 10s Andes de Catamarca, Argentina. Un total de 65 grupos de vicufia y 32 de guanaco fueron avistados. El tamaho medio de 10s grupos (4.8 individuos por la vicuiia y 3.5 individuos por el guanaco) ha resultado similar a 10s encontrados en otros trabajos, pero la frecuencia de guanacos solteros fuC muy alta. Posiblemente la segregacidn fuC obtenida por las dos especies mediante el uso de areas con distintas inclinaciones. Cuando fuC avistada, la mayorfa de guanacos y vicuhas estaba forrajeando. Las proporciones de individuos forrajeando, descansando y desplazandose fueron distintas en las dos especies. En particular el porcentaje de guanacos comiendo (94%) result6 mas alto de lo de las vicufias (69%). Las vicuiias se desplazaban en las primeras horas de la tarde y descansaban en las ultimas del dia. La diferencia de tamario de las tropas y de la actividad de 10s guanacos entre mi area de estudio y las otras puede ser en relation a su elevada altura. En esta area, . Fax: 39 577 298898 00921-448X/96/$15.00 0 1996 Elsevier Science B.V. All rights reserved SSDI 092 I -4488(95)00808-X