Common Marmoset (Callithrix (Callithrix) jacchus) is a New World monkey. It originally seemed to only live on the northeast coast of Brazil. It was recently found also in southeast Brazil.
The fur of the Common Marmoset is grey. The most distinguishing characteristic is the white, tufts of hair which surround the ears. A white mark is on the forehead and the face is hairless. The long tail is grey-white. Common Marmoset adult size ranges from 14 to 18 cm and they weigh approximately 400 g.
Like all hapalines, Common Marmosets are diurnal. Their habitat ranges from the edge of forests into the deep forests, but they also appear in fields. They can run swiftly along the branches of trees and are also excellent jumpers.
Common Marmosets live together in family groups of four to 15 animals, usually mated adults and their offspring. These groups inhabit territories of 30 hectares. The groups have a strict ranking, ordered by the dominance and aggressive behavior the group leader.
The diet of the Common Marmoset consists of insects, spiders, small vertebrates, bird eggs and tree sap.
Common Marmosets polyandrous; a female mates with several males, who then share in the care of the female and her young. After an approximately 150 day gestation, the female gives birth to up to four offspring, although twins are most common. Compared to adults, the young animals are very large. Newborn twins together are about 40% of the body weight of the mother and it is assumed that the polyandry and the paternal participation in the raising contribute to unusual child size. Males can mate after about one year, while females aren't fully mature until about 20 to 24 months.
The life expectancy of the Common Marmosets in the wild is about 10 years, although some living in captivity have lived to 16 years.
