Study of Social Interactions Among a Male-Female Pair of Eulemur mongoz Approaching Estrus

The purpose of this study is to examine social interactions in a newly-formed one-male/one-female group of semifree-ranging mongoose lemurs (Eulemur mongoz) at the Lemur Conservation Foundation (LCF) in Myakka City, FL. We conducted a preliminary study as to changes in social behaviors during a week leading up to the female’s estrus. The lemurs freely range in a mixed pine-scrub forest. We developed individual ethograms, wrote qualitative notes ad libitum, and collected focal animal and all occurrence observations for 6 hours 30 minutes each day Dec. 14-19, 2021. All lemurs were habituated to humans. Observations were conducted following LCF IACUC protocols. We observed proestrus behavior in olfactory communication. For both the female and male, total occurrences and average time spent marking (not sniffing) increased in three of the last four days. We also did not see any substantial changes in nearest neighbor distance. On average, the pair kept within 0.91 meters of each other throughout the study, with very little change daily. Most notably, unlike many other larger-grouped lemur species, we observed no evidence of female dominance. In none of the group travel did we observe the female actively lead throughout the travel. The male actively scooted back and forth ahead and behind her. We also observed only one bout of agonistic (contested) social behavior, the traditional indicator of dominance in primates. From our preliminary study, we suspect that while most social behaviors remain uniform, several aspects of social behavior change subtly as the female progresses through her estrus. Keywords mongoose lemur, Eulemur mongoz, estrus, proestrus, olfactory communication, scent-marking, dominance, semifree-ranging, social behavio