Lion tamarins have a varied diet, including fruits, flowers, birds eggs, insects and other small animals. Along their evolution, they have developed long, narrow hands with long fingers and clawlike nails that probe for insects in tree bark and between the lives and in the flowers of bromeliads, tropical plants often found attached to tree trunks.
Although many animals species show different color patterns between males and females, in golden lion tamarins both sexes have a bright orange coat. The high levels of the pigment phaeomelanin is responsible for this color. The distinctive fur color is likely to have played an important role in the natural selection of the species in the first stages of its evolution.
Golden lion tamarins live in families and protect their territory through scent-marking and vocalizations. They produce a sneezelike sound to communicate with other members of the same family, which can occupy an area of up to 100 acres. Although other monkey species also use vocalization to communicate, the golden lion tamarin's sneezelike calls are exclusive to the species. They are often related to dangerous situations, to feeding or to sexual receptivity.
In either side of each jaw, golden lion tamarins have two molar teeth instead of the three of other New World monkeys, primates native to Central and South America. This is adaptation is likely to be related to the reduced size of the species, in comparison to other New World monkeys. Canine teeth, especially in the lower jaw, are often smaller in golden lion tamarins.