Evaluating spatial distributions of scent-marks in semi-free-ranging groups of Lemur catta at the Duke Lemur Center
Committee members: Gebo, Daniel L.; Pingel, Thomas J.; Porter, Leila M.||Advisor: Irwin, Mitchell T.||Includes illustrations and maps.||Includes bibliographical references.
Abstract
Scent-marking is a widespread form of olfactory signaling exhibited in mammals and for a select group of primates. Although research exists on the process of scent-marking, surface preferences, and for the function of scent-marking in lemurs, analyses of how lemur group scent-marking distributions map onto their home range are lacking. The endangered ring-tailed lemur (Lemur catta) deposits scent-marks using its ano-genital, chest, and wrist glands. This project was designed to collect data on two groups of semi-free-ranging captive ring-tailed lemurs at the Duke Lemur Center to first assess how scent-marks are distributed within their home ranges; and second, to evaluate whether inter-sexual differences in scent-marking behavior occur. I collected observational and GPS offset data on the NHE2 and NHE4 groups of ring-tailed lemurs from May 22 to July 18, 2018. Data was analyzed with ArcMap 10.6.1 and R 3.5.1 software. Both groups clearly exhibited a territorial function of scent-marking. Scent-marks were generally deposited closer to the perimeter, those adjacent to other groups in particular, than the center of the home range. Common feeding sites were distributed in a similar manner. Neither group occupied their entire home range, and instead occupied areas closer to the perimeter. Scent-marking distributions were not merely a reflection of areas occupied by the groups. Furthermore, scent-marks were deposited at greater rates during intergroup encounters than in solitude. This finding suggested a secondary function for scent-marking involves intergroup communication, possibly for mate-guarding. Neither group exhibited temporal over-marking patterns. Males played a larger role in scent-marking than females. Over-marking patterns for both sexes suggested an over-marking function associated with intrasexual competition for access to mates. Upon comparisons with wild studies, it is evident that territoriality exists in both wild and captive conditions.
