Black howler monkey

Alouatta caraya

Black howler monkeys live in tropical rainforests and mixed deciduous forests in eastern Bolivia, southern Brazil and Paraguay, and northern Argentina. They are herbivores.

Black howlers are named for the loud howls, grunts, roars and barks they use to defend territory. Howling - done by the entire troop - is accompanied by shaking and breaking of branches. Howlers noises can be heard 1.8 miles away in the forest, and 3 miles away over water. This loud volume is a result of the monkey's deep jaw, and enlarged larynx and hyoid apparatus (a resonating chamber).

Black howler monkey behavior and facts

  • Black howlers spend up to 70 percent of each day lying and sitting quietly in branches, eating and fermenting leaves in their cecums (a large blind pouch that is the beginning of the large intestine). They also eat buds, flowers and fruit, particularly figs. As they eat, they may hang by their arms or tails.
  • They are diurnal (active in the day) and arboreal (live in trees), with short periods on the ground.
  • They move with a slow, four-footed gait. Their arms and legs are long relative to their body. The prehensile tail (one that can grab or take hold of things) functions as a fifth limb. When a monkey rests, its tail coils tightly around a branch.
  • Black howlers avoid leaping from branch to branch, but will make 3 to 4 yard leaps after much hesitation. They can swim if necessary.
  • Troop sizes range from 3 to 19. Troops commonly have 1 to 3 adult males and 2 to7 adult females.

From birth to death

  • Black howlers breed throughout the year with 7 to 15 months between births
  • Gestation: 180 to 194 days
  • Single births with occasional twins; young cling to the mother for 1 year
  • Sexual maturity:
  • Female: 3 to 4 years
  • Male: 5 years
  • Lifespan: 16 to 20 years; 25 years or more in captivity

Vital statistics

  • Males: 16 pounds, 18 to 28 inches with a 20 to 30 inch tail
  • Females: 13 pounds, 15 to 22 inches, with a 20 to 27 inch tail


Not listed

Black howlers, the Oregon Zoo and you

The zoo's black howlers live in the Amazon Flooded Forest exhibit. Their diet is monkey chow, vegetables, fruit and browse. Though in the wild they are hunted for food and captured for export, black howlers are not threatened due to their ability to adapt to many environments, their large range and their presence in protected parks and natural areas.