Head and body length is 175-310 mm and tail length is 250-440 mm. Weights range from 225-900 g. Some, such as in the hairy-faced group, have long hairs around the face and head. Some have mustaches while others have short white hairs which cover the entire area around the mouth. Coloration varies greatly among the species as do markings.

Preferred habitats are tropical forests, open woodlands, and secondary growth. They are diurnal and arboreal, traveling through the trees with rather quick, jerky movements. Social group structures and sizes vary amongst species as do the physical traits. Some species have been found cohabitating, and as a result these mixed troops are able to use information to find the best food sources.

In C. jacchus, breeding occurs seasonally. Usually 2 offspring are delivered after a gestation period of around 140 days after an estrous cycle of about 15 days. In females sexual maturity is reached at 18 months and 24 months for males. The father, as in other marmosets, helps with the delivery of its babies, receiving and washing them. When born, babies have very short hair. They cling very tightly to either parent, and will be transferred to the mother during feeding time. At 21 days, the youngsters begin to explore a bit, but ride on their parents backs until the age of 6-7 weeks.

C. jacchus is found on the Brazilian coast: in Piaui, Ceara, and the Pernambuco Provinces.