Denver Zoo Map

Alouatta caraya

Black Howler Monkey


Class: Mammalia
Order: Primates
Family: Cebidae
Genus: Alouattta
Species: caraya

Fun Facts

  • Howlers are the largest monkeys in the New World.
  • Howler monkeys spend 75% of their time resting, and rarely leave the trees.
  • Most of their diet consists of leaves.
  • Alouatta is the most widespread New World monkey genus.



Alouatta caraya are found in eastern Bolivia, southern Brazil and Paraguay and northern Argentina.


This species preferred habitats are rainforest and mixed deciduous forest.

Physical Description

  • Black and gold howler monkeys are about two feet (cm) long with a 30-inch (cm) tail.
  • Males weigh 11-18 pounds (5.0-8.3 kg); females weigh eight to 12 pounds (3.8-5.4 kg).
  • Males are covered with black fur; females have gold fur with a black face.
  • Howler monkeys have prehensile tails with bare skin on the underside.
  • Howler monkeys have large necks and lower jaws and super-sized vocal cords.
  • Like all howlers, their hyoid and larynx housing the vocal apparatus are enlarged.


What Does It Eat?

In the wild: Mostly leaf-eaters (folivorous), but they supplement their diet with fruit, flowers and seeds.
At the zoo: Fruits, vegetables and monkey chow.

What Eats It?

The black howler monkey is preyed on by harpy eagles and jaguars.

Social Organization

Black howler monkeys are social animals that live in groups of five to 19 individuals consisting of one to three adult males, two to four adult females and their offspring. There may also be bachelor groups. Alloparenting is practiced where other females of the group carry, groom, and protect infants other than their own. Alloparenting is sometimes practiced by the males of the group as well.

Life Cycle

Females mature at three to four years and males at about five years. Howler monkeys breed throughout the year in a polygynandrous system (both males and females breed with multiple mates). After a gestation of 180-194 days the female gives birth to a single offspring (twins are rare) weighing about three and a half pounds (113 g). The baby clings to mom’s belly for the first month then switches to her back. Young howler monkeys nurse for about a year and stay with their natal group until they reach adulthood. Average lifespan in the wild is 16-20 years and they live 23-28 years in captivity.


Calling Long Distance

Howler monkeys are noted for their remarkably loud guttural calls described as howls or growls. The male howler monkey has the loudest call of any primate. Their calls can be heard as far as three miles away. The angle of the lower jaw and the hyoid bone are greatly enlarged. These adaptations make possible the loud vocal resonations that amplify the sounds they project. These loud calls are used by male howler monkeys to communicate group location, distance and composition. Calls are also used to mark territory and keep intruders away.

Dimorphic Coloration

Male and female black howler monkeys look very different. Males are all black but the females have gold fur and a black face. This difference is called dimorphic coloration. All babies have gold colored fur when they are born, but by the time they are two and a half years old, the male’s fur color changes to black. The gold color of females and young may help them blend into the forest providing protection from predators.

Just Hanging Around

Howler monkeys have prehensile tails – a special feature that is useful for treetop living. Prehensile tails have a patch of bare skin on the underside of the last part of the tail that allows them to grasp branches. They rarely leap or jump from one branch to another. Instead they use their strong, muscular tails to anchor themselves as they climb in the trees. They use their tails to extend their reach and they can even hang from a tree by their tail alone.

Conservation Connection

IUCN Status: Least Concern.

The IUCN recognizes the black howler monkey as a least concern species only at the global level. In various areas of their range, they face increased threat by habitat loss of primary forests due to agriculture and ranching. They are also hunted for food and for their body parts. The hyoid bone is believed to have therapeutic properties and their skulls are sold for necklaces. Diseases such as yellow fever also threaten this species.

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