Howler monkeys are slow moving, thus easily falling prey to humans, where they are hunted for the large amount of meat on their bodies. Most of their time is spent in trees. They live in groups of from 8 to 20, with females outnumbering males. There is one dominant male per group. They do not groom each other, and this could account for the high incidence of disease among them.
Breeding takes place throughout the year, yielding one offspring.
The mother has complete control of the young. Howlers are the most widely distributed of the New World monkeys. They adapt well to the proximity of humans, and to deforestation, and are able to occupy small, isolated areas. In Argentina they often live near villages and are fed by people.