School of Human Evolution & Social Change, Arizona State University
Saturday 1:15-1:30, Grand Ballroom II
The extended primate juvenile period is likely a result of the complex interaction between feeding ecology and sociality. The Ecological Risk Aversion Hypothesis (ERAH, Janson and van Schaik 1993) has contextualized juvenility as a strategic life history shift that minimizes both predation and starvation risk. While this hypothesis fits the developmental patterns of skeletal growth in monkeys and apes, behavioral support for the ERAH in these taxa has been mixed. Furthermore, the ERAH is not supported by skeletal and dental development in the strepsirrhine, but behavioral evidence is lacking. A mixed-longitudinal sample of feeding and foraging behavior gathered from ring-tailed lemurs (Lemur catta) at the Beza Mahafaly Special Reserve, Madagascar shows that, like many monkeys and apes, ring-tailed lemur juveniles show a mix of behavioral traits predicted by the ERAH, but in general do not meet the ERAH’s predictions. Contrary to the ERAH juvenile ring-tailed lemurs do not show spatial patterning that would minimized predation risk (forage closer to conspecifics, forage in center of group), have higher dietary diversity, and are equally efficient at finding and eating leaves. As predicted by the ERAH, juveniles are less efficient than adult at processing fruits and feeding on flowers, and received more aggression than other group members. Using ring-tailed lemurs as an example it does not appear that lemurs show the same developmental tradeoffs as monkeys and apes, where ecologically risk aversive foraging may have broader impacts on growth and development.
This study was supported by the National Science Foundation (DDIG # 0851761), J. William Fulbright Foundation, Primate Conservation, Inc, and the ASU School of Human Evolution & Social Change.