“…Nevertheless, the reported range of variation is very wide for this species depending on different factors such as type of habitat and resource quality, heterogeneity and seasonality of the forest, competition with other species, disease, isolation and human intervention [Defler, 1981;Crockett and Eisenberg, 1987;Soini, 1992;Di Fiore and Campbell, 2006;Roncancio and Gómez-Posada, 2009]. For the genus Alouatta , high densities in fragments and islands have been reported in several different studies [Estrada and Coates-Estrada, 1996;Estrada et al, 2002;Ferrari et al, 2003, Van Belle andEstrada, 2006;Aguiar et al, 2009;Oklander et al, 2010].…”