Last Updated: Feb 13, 2013
Named for their throaty howls that can be heard for up to three miles, howler monkeys are the loudest of all New World monkeys. There are nine species of howler monkey, and Costa Rica is home to the common mantled howler, which inhabit parts of southern Mexico, Central and South America. Howler monkeys usually vocalize at dawn and dusk by passing air through a specially-adapted hyoid bone in their large throats. The result is a deep, grunt-like call that resonates for miles. These vocalizations are used to mark territory and communicate with others within the troop.
Scientific Name: Alouatta palliata
Status in the Wild: Common
Habitat: Cloud Forests, Rainforests, Tropical Dry Forests
Mantled howlers, called mono congo in Costa Rica, can weigh up to 20 pounds and typically have black fur. They are also noted for a brown or golden-colored mantle that is formed by long hairs along their flanks and back. Their long, prehensile tails act as an extra arm, gripping branches while they move about the rainforest canopy in search of food.
Howlers are considered folivores (an animal that eats primarily leaves) and also feed on flowers and fruit. They are arboreal creatures, spending most of their time in the treetops foraging for food, and rarely descend to the forest floor. Howler monkeys are the largest of all New World monkeys and have a lifespan of seven to fifteen years.
Mantled howler monkeys can be found in the canopies of both lowland and montane rainforests. They are commonly heard long before they are seen searching for leaves in the treetops. A troop of howler monkeys usually consists of eight to twelve females, three or four dominant males and several young. In Costa Rica, howler monkey sightings are common as they inhabit many of the country’s national parks and reserves, including Corcovado National Park, the dry forests of Santa Rosa National Park, Arenal Volcano National Park and the Monteverde Cloud Forest Reserve.
Females breed once every two years and typically give birth to one offspring after a six-month gestation period. With a year-round breeding season, males mate with several females and vice versa. An infant howler will cling to its mother’s belly for about a month and then catch a ride on her back. Mothers nurse their young for up to a year and have been known to care for abandoned or injured howler babies on occasion.
Status in the Wild:
The mantled howler monkey is protected by the Convention on International Trade in Endangered Species (CITES) program, which prevents international trading of the species. While their population is not considered threatened, the biggest concern is the destruction of their native habitat. In recent years, this has pushed the monkeys into human territory such as cacao and coffee plantations. Howler monkeys, like all species, play a critical role in the ecosystem by dispersing flower and plant seeds in their dung, which aids in rainforest habitat regeneration.