Morphometrics and pattern of growth in wild sifakas (Propithecus edwardsi) at ranomafana national park, madagascar

Abstract

We summarize morphometric data collected over a period of 22 years from a natural population of rainforest sifakas (Propithecus edwardsi) at Ranomafana National Park, Madagascar, and we use those data to document patterns of growth and development. Individually identified, known-age sifakas were successfully captured, measured, and released. We found that body segment lengths increased faster during growth than did body mass, with individuals attaining adult lengths earlier than adult mass. Females can begin reproducing before they are fully grown, but this may not be common. With the exception of hand length, we found no significant sex difference in any adult metric including body mass, chest, and limb circumferences, body segment lengths, and canine tooth height; however, body masses of individual females fluctuated more, independently of pregnancy, than did those of males. We found considerable interannual fluctuation in body mass with single individuals differing more within the same season in different years than from season to season in the same year. Such body mass fluctuation may be a consequence of eastern Madagascar's variable and unpredictable environment in which rainfall during any selected month varies from year to year.

The Nutritional Geometry of Resource Scarcity: Effects of Lean Seasons and Habitat Disturbance on Nutrient Intakes and Balancing in Wild Sifakas

“…The low lean season protein intakes reported here suggest that immature sifakas may fail to sustain growth in lean seasons. Although logistically challenging, it would be interesting to quantify mass change across seasons in adults [57] or determine whether juveniles’ growth is slowed or arrested in lean seasons [58]. In terms of reproduction, the observation that lemur species concentrate weaning in February/March, in the abundant season [59], is consistent with the idea that seasonality has placed high selective pressures on lemur life histories and may also explain why lemurs and other strepsirrhines have lower fetal growth rates than haplorrhines [60].…”

The influence of growth patterns on sexual size monomorphism in lemurs

“…The long and highly variable period of slow growth that follows weaning probably diminishes any limits to sexual size dimorphism imposed by a shortened period of rapid growth. Likewise, the age at which females first reproduce did not predict the duration of the second phase of growth in males or females, which is not surprising considering that lemur females can reproduce prior to reaching adult body mass (King et al ., ). However, the age at which females first reproduce was a significant predictor of the duration of the first phase of growth in both males and females.…”

“…Data on chronological age and body mass were obtained from the Duke Lemur Center's long-term records (Zehr et al, 2014) (Table S1; see King et al, 2005King et al, , 2011 for age estimation methods in the wild population). Studies have found tight correlations between wild and captive primate weights, including those measured at the Duke Lemur Center (Strum, 1991;Leigh, 1994;Terranova & Coffman, 1997).…”

Patterns of movement and seed dispersal by three lemur species

“…Among the frugivores in RNP, the large-sized lemur species, Propithecus edwardsi (mean body mass: 5.6 kg) [King et al, 2011] is primarily a seed predator, masticating the majority of seeds it consumes [Dew & Wright, 1998]. However, it is known to pass intact seeds when advancing age results in overly worn teeth [King et al, 2005].…”