Vicuña Vicugna vicugna are an emblematic species of one of the major arid ecosystems of the neotropics: the puna or altiplano. Excessive commercial hunting of vicuña for their valuable fleece in the past caused a severe decline in the population, with the vicuña almost becoming extinct by the mid 20th century. Effective protection resulted in the recovery of some populations and, recently, limited vicuña exploitation has been allowed. Research is urgently required to underpin the design of the management systems used for this exploitation. We present the results of a 2-year study on habitat utilization of vicuña in Laguna de Pozuelos UNESCO Biosphere Reserve in Argentina. Vicuña did not use the study area homogeneously but preferred vegetation communities dominated by grasses (known locally as pajonal and esporal) and with high overall plant cover. Vicuña were less selective in 2003, when overall habitat quality decreased, than in 2002. This change is predicted by habitat selection theory. We also found that members of family groups spend more time foraging than members of non-reproductive groups. Solitary vicuña spend more time standing up than members of groups, consistent with the observation that herding behaviour is related to protection against predators. Heterogeneous use and habitat selectivity suggest that exploitation of vicuña needs to take spatial behaviour into account in the establishment of the optimal location of capturing sites.