Mating Season Aggression and Fecal Testosterone Levels in Male Ring-Tailed Lemurs (Lemur catta)

Ring-Tailed Lemurs are diurnal, polygamous, and the female is only sexually receptive about 1 day a year. There is female social dominance over males, and the males do not care for the offspring.

The lemurs in this study are in an enclosed area, 9 hectares, and have been there for many years previous to the study. During the study, the ring-tails were also involved in a protocol that involved luring them into holding cages within the forest enclosure on a biweekly basis to collect blood samples and morphological measures.

During mating, different aggressive and submissive acts were recorded. Aggressive acts included

bite, lunge, chase, cuff, and grab. Submissive acts included jump away, flee, cower, and a high-pitch submissive vocalization, spat call, known to be the formal signal of subordination in this species. This was mostly between females. Males tendency to perform these actions correlated with sexual behavior, and their proximity to females.

"Look, I'm a big lemur because I stand taller than you!"

Their sexual behavior correlated directly with preestrus, estrus, and postestrus. Comparison of Serum and Fecal Testosterone Fecal testosterone level correlated significantly and positively with serum testosterone level among 9 adult ring-tailed males. Among 10 males, mean fecal testosterone levels increased significantly from the premating (October) to the mating period (December). Prior to the mating season the correlation between testosterone level and rate of aggression was not statistically significant, whereas during the mating season the correlation was positive and significant.

For most studies, fewer data allow for greater error in measurement and therefore reduced chances of

demonstrating significant correlations. Comparability of results from ring-tailed lemurs maybe due to the fact that mating system dynamics in this species resemble those of many nonmonogamous birds.

Cavigelli, S. and Pereira M. (2000), Mating Season Aggression and Fecal Testosterone Levels in Male Ring-Tailed Lemurs (Lemur catta). Hormones and Behavior, 37 no. 3. 246-255