Guianan Red Howler

The Guianan red howler (Alouatta macconnelli)* lives in Suriname, Guyana, French Guiana, Trinidad and Brazil, but like several New World monkeys its taxonomy and distribution are in dispute. Whatever the classification, red howlers are—in my humble opinion—the most beautiful of the New World monkeys. And the genus is common enough you’re likely to hear a howler’s magnificent roar at dusk or dawn throughout much of tropical Central and South America even if you miss seeing a shimmering reddish-brown howler. Red howlers like a variety of forest types, often with a lake or river edge, and can also live in small forest patches and secondary forests. Leaping and swinging is rare given their size—up to 20 pounds. Instead, they clamber, walk, or form bridges from branch to liana to branch. Their long red tails are prehensile but used more for hanging while reaching for food than travel.

Behavior and Communication

Alouatta macconnelli distribution map

Alouatta macconnelli distribution map

In Suriname, red howlers live in groups of up to eight monkeys with a dominant male. Most troops have only one or two males, the rest females and their offspring. Howlers have the loudest vocalization of any animal in the New World thanks to their bearded throats that house an extra-large hyroid bone. Primarily the males howl with a response from males in other howler troops. This allows troops to assign locations and ranges and avoid squabbles over scarce resources. Red Howlers have a specialized jaw and stomach to eat and digest leaves. They also eat sugary fruits, flowers, moss, bark and termite soil. Due to their primarily low energy diet, they spend up to 70 percent of each day resting, sleeping, and digesting. Like spider monkeys, red howlers eat but do not digest some seeds, which spreads their favorite food trees throughout the rainforest.


When mating, females attract males by moving their tongue rhythmically. If interested, males respond in kind; if not, females pick a new mate. Pregnancy is a little over six months and infants spend their first few months with their tail wrapped around their mother’s belly. Both females and males allow infants to crawl on them, although females are in charge of their offspring. Males are expelled from their birth troop upon reaching sexual maturity around age seven and forced to invade an outside troop. If successful, a male will kill the infants in his new troop to ensure future offspring are his own. Females reach sexual maturity around age five and may also emigrate to a new troop where they will compete with other females for entrance and mating.


The red howler’s main natural predators are harpy eagles, cats such as jaguars, pumas, and ocelots, foxes, spectacled caimans and snakes. Howlers are also hunted for food, both locally and for commercial export. Several Alouatta species are endangered but the Guianan red howler is not threatened. It is listed as a species of Least Concern on the IUCN Red List.

Alouatta seniculus is also used to describe all red howlers, with debate over the breakdown of subspecies.


So good I could watch these all day: ARKive Images of Life on Earth, Alouatta seniculus.


  • Boinski, S. De Apen van Suriname / The Monkeys of Suriname. 2002. Paramaribo, Suriname: Stichting Natuurbehoud Suriname.
  • IUCN Redlist
  • Primate Info Net

Featured Allouatta seniculus photo has been adapted from the original by Alessandro Catenazzi.

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