Black tailed Marmoset, Cuiaba, Brazil

The black-tailed marmoset (Mico melanurus) is a species of New World monkey from central South America, where ranging from the south-central Amazon in Brazil, south through the Pantanal and eastern Bolivia, to the Chaco in far northern Paraguay. It is the southernmost member of the genus Mico and the only where most of its range is outside the Amazon.
The black tailed marmoset is dark brown with paler foreparts and a black tail. Unlike most of its relatives, it has a striking white or yellow-white stripe that extends down its thigh. Its ears are naked, flesh-colored and stand out from the fur. They reach a size of 18 to 28 cm and weigh from 300 to 400 g.
Black-tailed marmosets are diurnal and arboreal, using their claws to climb trees. Originally rain forest inhabitants, plantations have caused them to expanded them their range. They spend the night in tree hollows or in very close vegetation. They live together in small groups and mark their territory with scent glands, driving out intruders by shouting or by facial expressions, including lowered brows and guarded lips. The diet of the black-tailed marmoset predominantly consists of tree sap. To a lesser extent, they also eat bird eggs, fruits, insects, and small vertebrates. Marmosets are very small monkeys. Most of the 22 different species are only about eight inches long (not including the tail). They are also fairly primitive with a less developed brain than other monkeys and several interesting physical characteristics like claws rather than nails and tactile hairs on their wrists. They lack wisdom teeth, and their brain layout seems to be relatively primitive. Marmosets are native to South America and have been found in Bolivia, Brazil, Colombia, Ecuador, Paraguay and Peru. They have also been spotted in Central America and Mexico. Marmosets are highly active, living in the upper canopy of forest trees, and feeding on insects, fruit, and leaves. They have long lower incisors, which allow them to chew holes in tree trunks and branches to harvest the gum inside; some species are specialised feeders on gum. The favorite food of marmosets is carbohydrate-rich tree sap, which they reach by gnawing holes in trunks. Their territories are centered on the trees that they regularly exploit in this way. The smaller marmosets venture into the very top of forest canopies to hunt insects that are abundant there. They are classified as least concern by IUCN.