The Common Marmoset (Callithrix jacchus) is a New World monkey. Common marmosets are native only to east-central Brazil. The word 'Marmoset' is from French marmouset, however the etymology is uncertain. In Modern French, they're called ouistiti. They have been introduced into other areas and live within the cities of Rio de Janeiro and Buenos Aires, Argentina. Marmosets can be found in a number of forest habitats. They live in Atlantic coastal forests as well as semi-deciduous forests farther inland. They can also inhabit savanna forests and riverine forests. Marmosets are successful in dry secondary forests and edge habitats.