Black howler monkey

Latin Name
Alouatta caraya




Black howler monkeys are sexually dimorphic-males are dark and larger in size than females, which are buff colored. Infants are born buff. All have dark, hairless faces with prominent jaws.



Central South America


Threatened by habitat loss and fragmentation due to cattle ranching and agricultural development for soy. Populations can adapt, however, to living in relatively small patches of undisturbed forest. Lincoln Park Zoo participates in the Southern Black Howler Monkey Species Survival Plan®, a shared conservation effort by zoos throughout the Association of Zoos and Aquariums.


From rain forests with near constant precipitation to tropical deciduous forests with changing seasons.


Howler monkeys live in large social groups comprised of family members. Females allomother—aunts and siblings will carry, groom and nurture newborns. Adult males will help, too. Maturing males leave their birth group to join another. Everyone howls in the morning to mark territory, offering a loud, deep roar.

Life History

Howler monkeys are promiscuous. Single births are nurtured for about a year before the dam begins mating again. After weaning, young begin eating fruit, flowers and plants like the adults.

Special Adaptations
  • Their molars are specially adapted for processing leaves, which they spend most of their day doing. These leaves are fermented in enlarged caecums within the howler monkey's gastrointestinal tract.
  • Strong prehensile tails enable howler monkeys to grip and hang from branches. The hairless underside is sensitive, enabling them to identify texture.
  • Oversized vocal features (larynx, etc.) enable howler monkeys to emit their titular calls.
  • Howler monkeys mark their territory with dung piles and scent markings on branches.

Bonus Content

A female black howler monkeys takes a closer look at a massive Chicago-style hot dog. (Photo by Anita Yantz)

Animals Eat the Skyline at Chi-Cow-Go
The zoo celebrated Chicago’s 175th birthday with a bovine bash. The fun kicked off with the unveiling of a redesigned "Cows on Parade" statue before moving to the rest of the zoo with Chicago-themed animal enrichment.