Common marmosets are native only to east-central Brazil. They have been introduced into other areas and live within the cities of Rio de Janeiro and Buenos Aires, Argentina.
The common marmoset’s claw-like nails, incisor shape, and gut specialization reflect their unique diet which is primarily made of plant saps and insects. Common marmosets feed on gum, sap, latex, and resin.
Common marmosets live in groups with only a few members allowed to breed. A marmoset group can contain as many as 15 members, but a more typical number is nine. A marmoset family usually contains 1-2 breeding females, a breeding male, their offspring and their adult relatives, be it their parents or siblings. The females in a group tend to be closely related and males less so. Males do not mate with breeding females that they are related to.