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


Seasonal variation in group movement patterns in the Sanje mangabey (Cercocebus sanjei), Udzungwa Mountains National Park, Tanzania

EMILY K. LLOYD and CAROLYN L. EHARDT.

Department of Anthropology, University of Texas at San Antonio

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Sanje mangabeys (Cercocebus sanjei) are an Endangered primate species restricted to the Udzungwa Mountains, Tanzania. When available, mangabeys feed on ripe fruit which are typically widely distributed within a home range. During the wet season, when ripe fruits are most available, daily paths are expected to be longer and more linear than during the dry season. Group location data were collected every thirty minutes using handheld GPS units during 67 full-day follows of a fully habituated Sanje mangabey troop (n = 39) between January 2005 and December 2007. Daily path lengths (DPL, m) and a measure of linearity (sinuosity) were calculated using Hawth’s Animal Movement Extension in ArcGIS. No significant seasonal differences were found in mean daily path length or mean path sinuosity, but Levene's tests revealed significantly larger variance in DPL during the wet season (F = 3.008, p = 0.038) and in sinuosity during the dry season (F = 6.546, p = 0.013). These results reveal an alteration in foraging strategy by season. During the wet season, Sanje mangabeys may travel long distances each day to reach ripe fruits, or may take advantage of large, slowly depleting patches on sequential days, resulting in a highly variable DPL. Foraging for dispersed food resources during the dry season may result in variable backtracking movement patterns which can account for higher variation in sinuosity. GIS technologies and associated inferential spatial statistics are becoming increasing important in examining the spatial dimensions of animal behavior, an under-studied aspect of primatology.

The Critical Ecosystem Partnership Fund, The Margot Marsh Biodiversity Foundation, Zoo Atlanta, The University of Georgia Research Foundation, WWF-Tanzania, Conservation, Food and Health Foundation, Wildlife Conservation Society, Conservation International, Primate Conservation Inc., Primate Society of Great Britain and British Airways.

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