The 82nd Annual Meeting of the American Association of Physical Anthropologists (2013)

Effects of predator presence on the behavior of bald-faced saki monkeys (Pithecia irrorata) in the Peruvian Amazon


1Anthropology, The Ohio State University, 2Anthropology, The University of Texas at San Antonio

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Predation is an important selective pressure on prey populations but its influence on primate evolution remains hotly debated. While some researchers argue predation has little effect on group-living in primates, others maintain that constant threats of death strongly impact behavior. Here, we explore the effects of predator presence on saki monkey (Pithecia irrorata) behavior. We hypothesized that saki monkey behavior would differ in high and low use predator areas.

Data were collected from June to July 2012 at Centro de Investigación y Capacitación Río Los Amigos in Peru. Over 78 hours of scan and focal sampling were collected on 8 saki monkeys. During 10-minute focal follows, we recorded activity, canopy height, intragroup spacing, vigilance, and number of alarm calls emitted. To determine high and low use predator areas, we conducted a 30-day camera trap survey within the focal group’s home range.

During 30 trap nights, we documented four felid species (jaguar, puma, ocelot, and margay) on 11 separate occasions. Camera trap data indicates a pattern of higher predator densities within parts of the sakis’ home range. Analyses of behavioral data suggest that sakis maintain closer associations and engage in less rest and social behavior in high predator areas (Chi-square: P<0.05). However, alarm calling and canopy height are not associated with predator presence (Chi-square: P>0.05). Surprisingly, individuals seem to exhibit less vigilance in high predator areas, which may be related to habitat differences. Our future research will include an assessment of factors such as habitat quality and seasonality on antipredator behavior.

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