Seasonal patterns of male affiliation in ring-tailed lemurs (Lemur catta) in diverse habitats across southern Madagascar

We examined the mechanisms guiding male affiliative relationships among ring-tailed lemurs (Lemur catta) to investigate the adaptive significance of male social bonds in a female dominant, strictly seasonally breeding strepsirhine primate. To test whether male affiliative relationships were driven by reproductive and/or ecological conditions, we compared the frequency of male affiliation across the annual reproductive cycle in populations of L. catta inhabiting three habitat types found within its geographic range: (1) gallery forest at Beza Mahafaly Special Reserve in southwestern Madagascar; (2) spiny bush at Cap Sainte-Marie (CSM) in southern Madagascar; and (3) rocky-outcrop forest fragments at Anja Reserve and the Tsaranoro Valley in Madagascar's south-central highlands. Each study period spanned the gestation, lactation/migration, post-migration, and mating periods. Inter-male affiliation rates varied across reproductive periods at each of the four sites, with the highest frequencies being observed during the gestation and lactation/migration periods and the lowest frequencies occurring during the mating period. In contrast, we found no clear patterns in male female affiliation rates with respect to reproductive period. Comparing the Beza Mahafaly and CSM populations, rates of inter-male affiliation were higher at CSM during the gestation and lactation/migration periods, and rates male female affiliation were higher at CSM across all seasons except the post-migration period. We suggest that inter-male affiliative relationships in L. catta may provide beneficial social interactions (i.e., grooming, ectoparasite control, predator protection, vigilance against extra-group male agonism) when females are unavailable, particularly during male dispersal, as well as under harsh climatic conditions characteristic of some L. catta habitats.