Social group dynamics and composition of managed wild vicuñas (Vicugna vicugna vicugna) in Jujuy, Argentina

Abstract

The vicuna is a high Andean wild camelid that lives year-long in groups. We analyzed the social organization of 98 marked vicunas after capture and live shearing, focusing on group composition, spatial patterns, territoriality and habitat use. The social units analyzed were families, bachelor groups and solo animals. Location fixes of 54 males and 36 females were registered over a 2-year period, and home range was estimated. All females belonged to family groups, and 8–12 month yearlings changed their home ranges prior to first reproduction at 2 years. Female yearlings dispersed to a new family group, while male yearlings dispersed to a bachelor group. Solitary males appeared during the interval between leaving bachelor or family groups, and vice versa. Our study showed that vicuna polygyny was based on female grazing area requirements. Females that stayed with the same males were defined as loyal, and had a mean 18.9 ha home range. Females that changed both to a different family and male; and grazed over the same home range size, were considered disloyal. Family groups selected the habitat that had a low stratum and the highest coverage of palatable plants, while bachelors used their habitat randomly.