1Anthropology, University of Wisconsin, Madison, 2Anthropology, The University of Texas at San Antonio
Friday All day, Plaza Level
Human/non-human primate interactions are increasingly common as human populations expand near primate habitats, making research on primate response to human presence critical for species living in anthropogenically impacted landscapes. Behaviors that prey species exhibit towards predators (including humans) such as greater levels of vigilance and reduced feeding time are known to limit population size, even when mortality from predation is low. Therefore, these behaviors may be used as indicators of human impact on primate populations. We investigated how Javan gibbons (Hylobates moloch) living in a human-impacted sacred forest (Cagar Alam Leuweung Sancang, West Java) adjust to varying levels of human exposure. Data were collected February-April 2009, and August 2010-July 2011. Preliminary analysis of 2 social groups indicates that as the number of encounters with humans increased, most (4/5) individuals reduced time spent feeding (B male 35%-0%, p=0.0014; B female 45%-0%, p=0.0112; C female 30%-23%, p=0.0028; C juvenile 25%-15%, p=0.001) and increased time spent resting. Also, as human encounters increased, male gibbons increased vigilance behavior (B male 10%-15%, p=0.0014; C male 5%-15%; p=0.0255), and female and juvenile gibbons spent more time in higher canopy (B female 23%-73%, p<0.001; C female 10%-50%, p=0.0702; C juvenile 5 %-50% p=0.0022). These results are consistent with the hypothesis that as human presence and encounter rates increase, gibbons alter their behavior in ways consistent with anti-predator behaviors. Assessing how this critically endangered species responds to human presence is a vital part of their ultimate conservation.
This study was funded by the Fulbright Foundation, Primate Conservation Inc., the International Primatological Society, UW Madison Division of International Studies, UW Madison Department of Anthropology, and the Hitchcock foundation.