Howler monkeys are one of the largest species of monkeys inhabiting the forests and savannas of South America. Being the loudest animals in the world, they are known for their distinctive calls that can be heard miles away. There are 9 different species of howler monkey. Howler monkeys inhabit the central parts of South America in Brazil, Bolivia, Argentina and Paraguay.

Howler monkeys are New World monkeys. Unlike Old World monkeys, New World monkey possess wide, side-opening nostrils and do not have pads on their rumps. They also have prehensile tails, or tails that can grip. Howler monkeys are diurnal; they are active during the day and sleep at night.

Howler monkeys possess large necks and jaws that enable them to make their loud vocalizations. They have long tails that help them to grasp branches and move through the forest canopies. Despite being large monkeys, howler monkeys weigh very little allowing them to move through the forest with great agility. Their light weight also allows howler monkeys to hang from branches by their tails.

Howler monkeys have beards and long, thick hair. Male howler monkeys and female howler monkeys have a very different appearance. Female howler monkeys have yellow to olive brown fur. Male howler monkeys have black fur. Male howler monkeys are larger than female howler monkeys.

Howler monkeys move in troops of up to 18 howler monkeys. The leader of a howler monkey troop is usually an elder male. Troop members spend much of their time grooming each other and sleeping. Howler monkeys are believed to be one of the least active monkeys.

Howler monkeys can project their voices for miles. Howler monkeys usually howl during the mornings and evenings to alert neighboring troops of their presence. Howling sessions involve the entire troop of howler monkeys. Howler monkey calls sound like a loud roar or whooping bark. After one troop of howler monkeys calls, another troop answers. Despite being territorial, howler monkeys rarely engage in conflict and sometimes even share an overlapping territory.

Howler monkeys feed mostly on eat leaves, but will sometimes eat fruit, seeds, flowers, buds and moss. Howler monkeys get most of their water from the food they eat.

Howler monkeys prefer not to jump from tree to tree, rather they use their hands, feet, or tails to hold on to one tree as they reach to the next tree. They will link together hand-to-tail between trees to create a bridge for young howler monkeys to walk across.

Howler monkey females usually have one baby each year. When howler monkey babies are born they are a light golden brown so they can hide in their mother’s fur. Girl baby howler monkeys maintain the light brown color fur. Boy baby howler monkey fur darkens to black in about three years.

Howler monkeys live to be around 20 years old. Being large animals, howler monkeys have few predators with the exception of harpy eagles and humans.

Howler monkeys are threatened with habitat loss from clear cutting and logging by the animal agriculture industry. Their populations are in decline, especially in the Argentinean provinces of Salta, Formosa, Misiones and Corrientes. The Yucatán Black howler monkey is endangered. Howler monkeys are also targeted for bushmeat.