Female age-specific reproductive rates, birth seasonality, and infant mortality of ring-tailed lemurs on St. Catherines Island: 17-year reproductive history of a free-ranging colony

To compare reproductive parameters of a managed population of free-ranging provisioned ring-tailed lemurs (Lemur catta) to wild L. catta populations, we analyzed birth and mortality records collected over the 17-year history of the St. Catherines Island ring-tailed lemur colony. The majority of births in this colony (approximately 80%) occurred in March, which indicates that most females at this site conceived during the first estrus cycle of the breeding season, as do wild ring-tailed lemur females (Sauther [1991] Am J Phys Anthropol 84:463-77). Females in this provisioned colony reach the age at first parturition (primiparous age) earlier (at 2 years) than do wild ring-tailed lemurs, which typically begin to reproduce at 3 years of age (Sussman [1991] Am J Primatol 84:43-58; Koyama et al. [2001] Primates 42:1-14; Gould et al. [2003] Am J Phys Anthropol 120:182-94). Female fecundity is lowest at 2 years of age (34%), but increases to 67-100% for females age 3 and older. Survival analyses showed that infant survivorship for very young (2-3 years) and very old females (> 10 years) are similar, and are lower than that for reproductively prime-aged females (4-9 years), although this trend is not statistically significant (chi(2) = 3.18, df = 2, n = 125, P = 0.203). There was a large amount of variability in infant survival rates among the oldest females, and a few older females (ages 13 and 14) still had high infant survival rates despite their old age. When compared to wild populations, provisioning in this island colony generally caused a decrease in the female primiparous age, a decrease in infant mortality, and an increase in multiple-offspring births (twins or triplets).