(Callithrix Jacchus), also common marmoset, a monkey of the genus Callithrix. The body length is 17 to 20 cm, and the tail length, 24 to 37 cm. The pelage is long, with black and gray annulations, which are especially noticeable on the tail. There are long, white tufts on the ears. The face is covered with hair, and there is a white, rhomboid spot on the forehead. The wistiti is distributed in the equatorial rain forests of Brazil, south of the Amazon. It lives in tall trees in groups of three to eight individuals and feeds on insects and fruits. It bears two offspring at a time.