“…Researchers of a variety of nonhuman primate species under naturalistic conditions have reported "forced copulation" or "rape" as relatively rare episodes occurring over many hundreds (if not thousands) of observation hours: slender loris (Loris lydekkerianus) (Radhakrishna & Singh, 2004), ring-tailed lemur (Lemur catta) (Parga & Henry, 2008), mantled howler monkey (Alouatta palliata) ( Jones, 1985( Jones, , 2002, white-bellied spider monkey (Ateles belzebuth) (Gibson et al, 2008), southern muriqui (Brachyteles arachnoides) (Milton, 1985), samango monkey (Cercopithecus mitis) (Henzi & Lawes, 1987), patas monkey (Erythrocebus patas) (Chism & Rogers, 1997), long-tailed macaque (Macaca fascicularis) (Engelhardt et al, 2006), bonnet macaque (Macaca radiata) (Singh, Kumara, Ananda, Singh, & Cooper, 2006), and chimpanzee (Pan troglodytes) (Goodall, 1986;Stumpf & Boesch, 2006;Tutin, 1979). The relatively small number of relevant data and variable outcomes limits causal and functional analyses of the behavior in these cases.…”