Behavior, Ecology, and Demography of Aotus vociferans in Yasuní National Park, Ecuador

Abstract

Given its broad geographical distribution, Aotus is a productive genus for comparative studies that evaluate how different ecological factors influence the morphology, behavior, ecology, and demography of closely related species. During 18 mo we collected demographic, ranging, and activity data from owl monkeys (Aotus vociferans) in Yasuní National Park in eastern Ecuador. To collect demographic data, we monitored the trail system several times per week searching for groups. To characterize patterns of activity, we recorded the time when the subjects began and ended their nocturnal activity, and we collected data on range use and daily path length during 12 full-moon and 12 new-moon night follows of 1 radiocollared group. They ranged in size between 3 and 5 individuals (n=4 groups). All groups were strictly nocturnal, beginning their activity between 1800 and 1900 h and finishing it between 0500 and 0600 h. The territory size of the radiocollared group was 6.3 ha. On average, the subjects traveled 645 m per night (±286 m) and ranged farther during full-moon than new-moon nights. The owl monkeys used a small number of preferred daytime sleeping trees. Our data conform well with previous studies of other tropical owl monkeys from Colombia and Perú. A comparison of tropical owl monkeys with more temperate Aotus azarai from the Int Argentinean Gran Chaco reveals that grouping patterns, day range length, and territory size are relatively conserved across the genus despite dramatic differences in body size and activity pattern.

Research and in situ conservation of owl monkeys enhances environmental law enforcement at the Colombian‐Peruvian border

“…We still do not know the ecological impacts caused by the release of, for example a population of 278 animals subjected to investigations into malaria, on resident populations. As territorial species living in groups of no more than five individuals, there are likely impacts on; competition for food, territory, behavior and of course health [Aquino & Encarnacion, 1994;Fernandez-Duque, 2007;Fernandez-Duque et al, 2008]. Maldonado [2013] and RuizGarcia et al [2013] also suggested that the releases of A. nancymaae in Colombia for more than three decades, not only created an introduced population of A. nancymaae, but also might have displaced wild populations of A. vociferans at the release sites.…”

Mated pairs of owl monkeys (Aotus nancymaae) exhibit sex differences in response to unfamiliar male and female conspecifics

“…Therefore, the cost of cuckoldry is high for socially monogamous males. Mate-guarding by male owl monkeys may reduce their risk of cuckoldry, given that female owl monkeys are widely dispersed [Aquino & Encarnacion, 1986;Fernandez-Duque et al, 2008;Wright, 1985], rendering any olfactory cues about changes in their reproductive condition not immediately accessible to their mates if they are not nearby and females display no visible signs of ovulation [Dixson, 1983]. Also, given that visibility is one of the main factors that determines the monopolizability of females [Schulke, 2002] and that owl monkeys are nocturnal, it is reasonable to suggest Am.…”

Predation and Predation Attempts on Red Titi Monkeys (Callicebus discolor) and Equatorial Sakis (Pithecia aequatorialis) in Amazonian Ecuador

“…The primate community of 10 different species has been studied extensively [Di Fiore, 2001;CarrilloBilbao et al, 2005;Di Fiore and Fleischer, 2005;Di Fiore et al, 2007;Fernandez-Duque et al, 2008;Di Fiore et al, 2009]. Between July 2004 and December 2008, researchers in the area spent approximately 25,000 h in the forest studying 7 primate species.…”