Ecological, behavioral and demographic aspects of natal dispersal in monogamous owl monkeys (Aotus azarai) of the Argentinean Chaco.

EDUARDO, FERNANDEZ-DUQUE; CECILIA PAOLA, JUAREZ

Edinburg

Congreso; International Primatological Society; 2008

Primate Society of Great Britain

This study describes the behavioral mechanisms regulating natal dispersal in owl monkeys and examines some of the demographic and ecological factors that may trigger dispersal.  Owl monkeys (Aotus azarai) are small, territorial primates that live in socially monogamous groups in the Argentinean Chaco.  Between 1997 and 2007 we recorded the disappearance or dispersal of 150 individuals born in 26 social groups.  We also collected behavioral data on the social circumstances surrounding the dispersal of 10 males and 11 females (n=11 groups, approx. 300 hs).  To characterize the actual process of dispersal (e.g. distance dispersed, time spent dispersing), we contacted regularly 17 radio-collared individuals until they disappeared, entered a new group or died.  All individuals left their natal group, and they did so when they were between 2.2 and 4.9 years of age.  Pre-dispersal peripheralization was reflected in an increased distance between the dispersing individual and the adults, and the frequent use of different trees for sleeping or foraging.  Some individuals ranged repeatedly outside their parent’s territory for periods of several hours to a few days before their definite dispersal.  Most dispersal events occurred immediately before or during the birth season, but the exact timing could not be reliably predicted by any ecological (e.g. food availability, temperature) or social factor (e.g. increase in group size, birth of sibling, eviction of parents).  An extremely flexible dispersal strategy seems most adaptive for owl monkeys given the intense competition for reproductive positions in this population.