They may hang from a branch by their arms or tail, but they do not swing through the trees. They walk on top of the branches. The average size of the groups is 18 individuals. There are more males than females in a group. Adolescent males often are found by themselves.
Howlers are very territorial.
They protect their territory from others by howling, shaking and breaking branches. They rarely fight. There is no clear dominante male, even during the time a female is sexually receptive. The males as well as the females will help an infant bridge a gap between two branches, or retrieve them if they fall.