There are several species of marmosets. The common marmoset species is easily identified by the two white tufts of hair at the sides of the head and a white blaze on the forehead. Its body is covered with short, thin hair grayish in color with darker stripes. The marmoset lives in family groups of 3-8, but may be seen in groups of considerable size.
Marmosets run and hop in trees and bushes, and are capable of leaping from branch to branch.
They have overlapping home ranges and do not defend their territories. Dominance is maintained through aggressive interaction and vocalizing. They devote much time to mutual grooming. By night they sleep in hollows of trees or hidden among vegetation. The life span of marmosets seems to be approximately 10 years in the wild.