The Common Marmoset Callithrix jacchus is a New World monkey. Like other marmosets, the Common Marmoset has claw-like nails which help them to climb. They use their claws to gouge holes in trees and then eat the sap that is released. They have specialised teeth to create these holes in the tree trunks. Claw-like nails help the marmosets in their squirrel-like movement, allowing them to run vertically up trees, across branches and leap between trees.
In the wild, there are usually 10–12 marmosets in a troop and often only one pair breeds. The breeding male and female tend to share dominance. Females choose their mate. The males and older siblings carry the very young.
Dominance is maintained though various behaviours, postures and vocalizations and subordinates will groom their superiors.
Marmosets use scent glands to mark objects. These are meant to communicate social and reproductive status.