Lincoln Park Zoo

Common name: Black howler monkey Latin Name: Alouatta caraya Class: Mammals Order:    Primates Description 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.

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Range
Central South America

Status
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.

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

Niche
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. This call is 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 GI 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.