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Red howler
Alouatta seniculus

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CITES: Appendix II (What is CITES?)
IUCN Red List: A. macconnelli, A. sara, A. seniculus: LC (What is Red List?)
Key: LC = Least concern, LC = Least concern, LC = Least concern
(Click on species name to see IUCN Red List entry, including detailed status assessment information.)

Alouatta seniculus
Photo: Luiz Claudio Marigo

Red howler monkeys are adaptable and are capable of living in small patches of forest (Phillips & Abercrombie 2003). A population can live in 1 sq. km (0.4 sq. mi) forest fragments, one group can survive in a 0.1 sq. km (.04 sq. mi) fragment and a 0.01 sq. km (.004 sq. mi) forest fragment can possibly support red howlers if they are able to alter their ecology somewhat (Gilbert 2003). In addition, because of their ability to disperse, they are resilient in areas where other primates have disappeared from a particular habitat (Hernández-Camacho & Cooper 1976; Defler 2004).


Threat: Human-Induced Habitat Loss and Degradation

The most pressing threat to the red howler, like other primates is habitat destruction (Defler 2004). Because seasonally flooded forests are inhabited by red howlers, they have the potential to be adversely affected by both the damming of rivers as well as logging along the edges of rivers (Ayres 1982).

In Trinidad, where A. macconnelli populations are considered vulnerable by the IUCN Red List, the main threats to the habitats of the species are illegal logging, forest clearance for agriculture and destruction resulting from oil exploration (Hsu & Agoramoorthy 1996).

The building of hydroelectric dams can also profoundly alter red howler habitat. In one case of a dam in Venezuela, howlers formerly inhabiting both sides of a river are now restricted to islands in a catchment lake for the dam resulting in their isolation from other populations and the disappearance of some groups (Norconk 1997).

Threat: Harvesting (hunting/gathering)

Howler monkeys are one of the most widely hunted primate taxa in the neotropics and are choice prey items even in areas which are only marginally under hunting pressure (Peres 2000). However, the degree of hunting of red howlers is variable between locations (Hernández-Camacho & Cooper 1976; Defler 2004). In habitats in the western Brazilian Amazonian seasonally flooded forests, red howlers are a preferred subsistence prey during high water, because fishing is precluded by the floods (Peres 1997a).

In Trinidad, hunting is a significant threat to red howlers even though it is illegal. In areas around wildlife sanctuaries on the island, up to 85% of individuals interviewed admitted to eating or hunting monkeys for meat (Hsu & Agoramoorthy 1996).

In Colombia, red howlers are also sometimes killed and taken for their enlarged hyoid, which is used as a drinking vessel to treat goiters. A minor hunting threat to the red howler is killing for its skin, but this occurs only occasionally (Hernández-Camacho & Cooper 1976).

Threat: Pollution

Oil pollution has the potential to threaten red howler populations on Trinidad, as pipelines and allocation wells leak into the local water supply. Large mammals drink from the water supply and thus red howlers might potentially affected by such leaks (Hsu & Agoramoorthy 1996).

Threat: Intrinsic Factors

Red howlers are susceptible to a number of intestinal parasites, including those of the genera Strongyloides, Trichuris, Chilomastix, Blastocystis and Iodamoeba which have the potential to cause parasitic infections and potentially represent a threat to members of the species (Phillips et al. 2004). They are also susceptible to a number of other maladies in their natural habitat (de Thoisy et al. 2001).




Content last modified: November 26, 2007

Written by Kurt Gron. Reviewed by Carolyn Crockett.

Cite this page as:
Gron KJ. 2007 November 26. Primate Factsheets: Red howler (Alouatta seniculus) Conservation . <>. Accessed 2019 March 21.