Do Habitat Use and Interspecific Association Reflect Predation Risk for the Golden-Headed Lion Tamarin (Leontopithecus chrysomelas)?

Predation risk may affect the way species use their habitat. Interspecific associations can help to improve predator detection and avoidance. The golden-headed lion tamarin (Leontopithecus chrysomelas) is an endangered primate of the Brazilian Atlantic Forest whose geographical range is dominated by shaded cacao agroforest (cabruca), where predation risk is high and mainly due to raptors. We investigated whether predation risk affects vertical stratum use and time spent traveling by tamarins, and the role of interspecific association with Wied’s marmosets (Callithrix kuhlii) in shaping these activities. We compared the behavior of three tamarin groups in cabruca (March 2010–June 2011) with that of three groups in mosaic forests (January 2007–December 2008), where predation risk is lower. We predicted that tamarins would use the higher strata level less in cabruca than in mosaic forests, and would use it less after encounters with predators than before such encounters. We also predicted increased use of the higher level and increased travel during interspecific associations than when tamarins were alone. We found that tamarins avoided the higher level regardless of habitat, but used it more often in cabruca than in mosaic forest, and did not avoid it after encounters with predators. Interspecific associations did not influence tamarins’ activities, except for the smallest group of tamarins in mosaic forest, which decreased its use of the lower level when in an interspecific association. Our results suggest that the benefits of interspecies association are not related to the activities investigated here, and that predation risk can influence habitat use but vegetation structure may constrain its optimal use by primates, increasing their vulnerability to predation.