Howler Monkey, a New World monkey. There are six species. Howler monkeys are the largest of the New World monkeys; they are about three feet (90 cm) long, including the prehensile (grasping) tail. Howler monkeys are black or brown. The throat is greatly enlarged by a bony, drumlike soundbox that produces a howl that can be heard for great distances. Howler monkeys live in small troops in the jungles of Central and South America. They feed chiefly on leaves, fruits, and budding twigs. Due to habitat destruction, the existence of most species is threatened.
Howlers live in a wider range than any other New World monkey—from southern Mexico to southeastern Brazil.
Howlers also live in more types of habitats than any other group of New World monkeys. They live in rain forests, thorny forests, swamp forests, and misty forests, high in the mountains.
Mantled howlers prefer to live in old-growth forests that have very old and very big trees. Red howlers live in old-growth forests, too. But these monkeys also live in forests made of young trees. Brown howlers like mountain forests. Red-handed howlers like forests that flood.
Howlers hang out very high up in treetops. They spend most of their time in the middle or at the top of the forest canopy. The canopy is a covering formed by the crowns, or tops, of trees.
Howlers, like some other New World monkeys, have prehensile tails. A howler can use its strong, flexible tail as a fifth hand. The tail is so powerful that a howler can hang by it alone. The underside of the tip has bare skin instead of fur. A howler can use this area to feel things, just as we use the palms of our hands.
Howlers climb and walk around the vines and treetops on all four feet. They move slowly and carefully. Howlers wrap their tails around tree trunks and branches as they go. This helps them keep a safe grip.
Howlers live in groups that usually have 15 to 20 members. The group is called a troop. Each troop normally has several adult males, a larger number of adult females, and young ones of different ages.
Members of the troop keep watch over one another. They warn each other when they spot a predator.
A dominant male, which is usually the largest howler, is the troop leader. He gets a lot of attention and affection. He also has first choice of food and mates. Each troop may also have a female that is dominant over other females in the group.
When young male howlers are fully grown, they usually leave the troop. They may join another troop or start their own. This gives them a chance to become leaders. This also helps keep the first troop peaceful. If a howler troop has too many young males, fights may break out.