INIBIOMA   20415
INSTITUTO DE INVESTIGACIONES EN BIODIVERSIDAD Y MEDIOAMBIENTE
Unidad Ejecutora - UE
artículos
Título:
Cooperative vigilance: the guanaco´s (Lama guanicoe) key antipredator mechanism
Autor/es:
TARABORELLI P.; P. GREGORIO; P. MORENO; A. J. NOVARO; P. CARMANCHAHI
Revista:
BEHAVIOURAL PROCESSES
Editorial:
ELSEVIER SCIENCE BV
Referencias:
Lugar: Inglaterra; Año: 2012 vol. 91 p. 82 - 89
ISSN:
0376-6357
Resumen:
The concept of sociality has been associated with the effectiveness of antipredator mechanisms, like cooperative vigilance and the dilution effect. Lama guanicoe (guanaco) is a social native herbivore in South America. The objective of this study was to evaluate antipredator mechanisms in guanacos by studying antipredator responses of guanaco groups of different sizes and in areas with varying predation risks. We measured antipredator responses to a human subject as potential predator. Detection of predator and flight distances from the predator both increased with a greater number of guanacos per group and with greater distances among guanacos within the social group. Both buffer distance and flight time decreased with a greater number of guanacos per group, but increased with greater distances among guanacos inside the group. Solitary adult males moved shorter distance and mixed groups moved greater distances. Flight distances were greater in areas with tall and dense vegetation than in areas with low vegetation. Buffer distance and flight time were shorter in undulating land than on flat lands, and guanaco groups were frequently observed on hill slopes. Our results suggest that the benefit of social grouping in guanacos, through its increased in the probability of avoiding predator, results from cooperative vigilance and not from the dilution effect. This means that a predator could be detected earlier, and thus be avoided more likely, when approaching a guanaco group than when approaching solitary individuals and could thus be avoided.