Abstract # 999 Event # 99:

Scheduled for Friday, August 19, 2005 10:00 AM-10:15 AM: Session 7 (Parliament Room) Oral Presentation

Aseasonal Births and Reproductive Patterns in Eulemur rubriventer in Southeastern Madagascar

S. Tecot and D. Overdorff
University of Texas- Austin, Dept. of Anthropology, C3200, Univ. of Texas-Austin, 1 University Station, Austin, TX 78712, USA
     Many lemurs are seasonal and synchronous breeders entrained by photoperiod. The window of reception is brief, lasting only a few hours per year in some species. This highly seasonal behavior has been considered to be one of the keys to understanding the socioecology of lemurid primates (Energy Frugality Hypothesis, Wright 1999). However, there is growing evidence that wild lemurs are not completely entrained to photoperiod although seasonality may still play a critical role in infant survivorship. Here we report the presence of aseasonal and asynchronous breeding, and multiple periods of receptivity in Eulemur rubriventer in southeastern Madagascar. Birth data were collected on five groups as part of a two-year study on reproductive hormones and were supplemented with demographic data on three groups from 1988-2002. None of the seven infants born more than two months outside the normal birth season lived. Successful births (infants living through their first year) occur every two years, as seen in other species and singleton births are not always the rule (twins, n = 7). Although these data suggest that E. rubriventer are not completely entrained to photoperiod, they still lend support to the Energy Frugality Hypothesis, which suggests that interspecies synchronized weaning during the time of year when food is likely abundant may be an adaptation to enable high energy intake during the time of highest energetic need.