Primates in Peril

Brown Spider Monkey
Ateles hybridus (I. Geoffroy Saint Hilaire, 1829)
Colombia, Venezuela
(2004, 2006, 2008, 2010, 2012, 2014)
Andrés Link, Pablo Stevenson & Ana Gabriela de Luna
Variegated or Brown spider monkey (Ateles hybridus hybridus,
left and center, and Ateles hybridus brunneus, right)
(Illustrations: Stephen D. Nash)
Brown spider monkeys (Ateles hybridus) are restricted
to Colombia and Venezuela, occurring in the middle
Magdalena river valley, extending into northeastern
Colombia and western Venezuela (Defler 2003) and
an isolated population in northeastern Venezuela.
Brown spider monkeys are considered to be Critically
Endangered due to habitat loss and fragmentation,
hunting and the pet trade (Morales-Jiménez et al.
2008a,b; Link et al. 2013). Recent phylogenetic studies
provide evidence that populations of brown spider
monkeys in the eastern and western banks of the
Magdalena river have had gene flow between them and
do not form monophyletic clades, thus questioning
the validity of its subspecific classification (Link et al.
2015). Nonetheless, further studies should explore if
populations nearer to the headwaters might be hybrids
of more distantly related populations in the northeastern
and northwestern areas of their distribution.
Spider monkeys are large-bodied primates with
extremely slow reproductive cycles in which females
have their first offspring at the age of 7 to 8 years,
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and give birth to a single offspring every 3-4 years. In
addition, they use large areas of undisturbed forests
(when available) where they feed preferentially on a large
variety of ripe fleshy fruits (Di Fiore et al. 2008). Thus,
spider monkeys are especially vulnerable to hunting and
are one of the first vertebrates to go locally extinct under
anthropogenic pressures to their habitat or populations.
Historically, A. hybridus has suffered from habitat
destruction and fragmentation and is absent from
heavily intervened areas (Link et al. 2008). In Colombia,
less than 18% of its historical distribution remains in
forested habitats and