male howler monkey

Black Howler Monkey

Alouatta caraya

CLASS Mammalia | ORDER Primates | FAMILY Atelidae

RANGE Eastern Bolivia, southern Brazil and Paraguay, and northern Argentina

HABITAT Prefer tall, aged forests; occupy the middle and upper canopies of the trees

DIET Canopy leaves, fruits such as figs and plums, buds, flowers and sometimes nuts

12 - 20 lbs

Body 15 - 28 in
Tail 20 - 30 in

180 - 194 days

1 - 2 (Usually 1)

IUCN Status
Least Concern
female and juvenile howler monkey

Males and females are sexually dimorphic; adult males are black, adult females and juveniles are a golden tan color. They are arboreal, diurnal, and have a prehensile tail.

Troop sizes range from 3 to 19. Troops commonly have 1 to 3 adult males and 2 to 7 adult females.

male howler monkey

Howler monkeys are the loudest primates in the Americas. Males do most of the howling. They can be heard 1.8 miles away in the forest, and 3 miles away over water.

The hyoid bone in their throat is modified and forms a bony box called a corniculum. The corniculum is an egg-shaped pouch that acts as an amplifying chamber, enabling these monkeys to out-howl all other land animals. They use loud howls, grunts, roars and barks to defend territory.

juvenile howler monkey

Black howler monkeys face threats from habitat loss due to agricultural development.