Taxonomy & Occurrence
Alouatta caraya is a monotypic species (no subspecies), but more research is needed to clarify its taxonomy [see 1]. It is found in Argentina (Formosa, Chaco, Santa Fé, Misiones, Corrientes), Bolivia, Brazil (Brasília Distrito Federal, Minas Gerais, Mato Grosso do Sul, Paraná, Rio Grande do Sul, São Paulo, Goiás, Bahia) and Paraguay .
IUCN Conservation Status
Like many New World primates, howlers have strong prehensile tails which serve as a fifth limb. Among the largest of New World monkeys, they are also unique in that their diet includes a large proportion of hard-to-digest, low quality mature leaves. Consequently, substantial time is spent doing nothing.
While trichromacy is the norm for all Old World monkeys, apes, and humans, in most species of New World primates, males are dichromats and about 60% of females are trichromats. Only the Alouatta is trichromatic for both sexes .
Juvenile and adult howlers being vigilant
Las Pampas, Bolivia
Seeing this Species
Howlers owe their name to their powerful "howling" calls. Hearing howlers howl is one of those special moments for the primate watcher, as wonderful as the gibbons' (Hoolock, Hylobates, Nomascus, Symphalangus) duets and the song of the Indri. The sound can best be described as prehistoric. It sounds more dinosaur than monkey. Widely considered to be the loudest land animal, their vocalizations can be heard clearly for 4.8 km according to the Guinness Book of World Records. So, even if you hear them, they may still be a few kilometers away. If you're lucky, you may get to catch them in the act: head back, throat pouch inflated. They shake and roar like the most excited dog, howling after a passing ambulance.
According to scientists, Madidi National Park could be the world's most biodiverse place for mammals, birds, butterflies, and plants, boasting nearly 9,000 species of fauna and flora  in an area of about 19,000 square kilometers. Dr. Robert Wallace, an ecologist with the Wildlife Conservation Society in Bolivia, referred to Madidi as “a place where the Amazon meets the Andes.”
Probability of success: ◆ ◆ ◇ ◇ ◇
Overlapping species: Madidi National Park is home to 9 other taxa of primates
Bolivian Red Howler (Alouatta sara)
Bolivian Night Monkey (Aotus azarae boliviensis)
Madidi Titi (Callicebus aureipalatii)
Shock-headed Capuchin (Cebus cuscinus)
Spix's White-fronted Capuchin (Cebus unicolor)
Peruvian Woolly Monkey (Lagothrix cana tschudii)
Weddell's Saddle-back Tamarin (Saguinus weddelli weddelli)
Bolivian Black-capped Squirrel Monkey (Saimiri boliviensis boliviensis)
Large-headed Capuchin (Sapajus macrocephalus)
 Nascimento F.F., Bonvicino C.R., da Silva F.C., Schneider M.P. & Seuánez H.N., 2005. Cytochrome b polymorphisms and population structure of two species of Alouatta. Cytogenetic Genome Research 108: 106-111.
 Fernandez-Duque E., Wallace R.B. & Rylands A.B., 2008. Alouatta caraya. The IUCN Red List of Threatened Species. Downloaded on 20 October 2019.
 Jacobs G.H., Neitz M., Deegan J.F. & Neitz J., 1996. Trichromatic colour vision in New World monkeys. Nature 382: 156-158.
Page Last Updated: 20 October 2019