The Cottontop Tamarin, also known as the Pinché Tamarin, is a small New World monkey weighing less than 1lb (0.5 kg). It is found in tropical forest edges and secondary forests where it is arboreal and diurnal. This tamarin species has a long sagittal crest, white hairs from forehead to nape flowing over the shoulders ("Cottontop"). The back is brown, and the underparts, arms and legs are whitish-yellow. Rump and inner thighs are reddish-orange. It is considered one of the bare-faced tamarins because of the lack of facial hair. Its lower canine teeth are longer than its incisors, so it seems as if it has small tusks. It is about the size of a squirrel and weighs 10-18 ounces. The males are only slightly larger than females. A medium Cottontop Tamarin weighs 432 g. Tamarins are among the smallest of the primates. Head body length of this species is 17 cm and tail length is 25 cm. Forelimbs are shorter than the hind limbs. The thumb is not opposable and the tail is not prehensile. All the finger and toe nails are like claws except for the big toe which has a flat nail. It moves from tree to tree by running or walking quadrupedally along horizontal branches and leaping as much as three meters between branches. It moves with quick, jerky movements. It is very alert and active. Claw-like nails help it to grip branches, since its small size and non-opposable fingers make encircling difficult. Long limbs and a long tail make it suited for jumping.

The Cottontop Tamarin is most active between sunrise and sunset (diurnal), it spends a large portion of its activity time foraging for animal prey, searching through leaves and along branches, and peering and reaching into holes and crevices in branches and tree trunks. It sleeps in broad tree forks or cavities When alarmed or excited, Cottontop Tamarins raise the hair on the crown of their head and stand up tall to make themselves look bigger. Groups of Cottontop Tamarins usually include 3–9 individuals. Group members are not necessarily all related. In addition to a dominant mated pair and their young, there may be transient individuals, probably young animals of both sexes. The home ranges of adjacent groups overlap. Research shows cottontops to be cooperative and pacifist to a surprising degree. All group members, even newcomers, take some part in carrying the young and giving them food morsels, particularly insects, and to the breeding female and infant carriers. The adult "helpers" gain experience in parenting by sharing in these tasks. Like most tamarins, the Cottontop Tamarin usually gives birth to twins, although single births and triplets happen occasionally. Tamarins reproduce year round with a gestation of 183 days. Both parents care for the young. Males and juveniles usually carry the young, giving them to the females for nursing. The newborn have a coat of short hair and are helpless. Newborns are able to cling tightly to the body of the mother or father by using their hands and feet. The father carries the young, but transfers them to the mother at feeding time. Weaning begins at four to five weeks and youngsters reach sexual maturity at 12 to 15 months. The Cottontop Tamarin will mark its territory with its scent by sliding its rear, or by rubbing the scent on the bottom of its feet. When coming into contact with other groups, instead of physical contact it will threaten the other group with the showing of its rear as a territorial display.

Its diet largely consists of insects, ripe fruit, seeds, nectar, and gum from trees that has oozed out. Other foods include some tender vegetation, spiders, small vertebrates, and bird's eggs. Mice, frog, bird and lizards are skillfully killed by a quick head bite, a learned behavior. The Cottontop Tamarin vocalize with birdlike whistles, soft chirping sounds, high-pitched trilling and staccato calls. Researchers say its repertoire of 38 distinct sounds is unusually sophisticated, conforming to grammatical rules and able to express curiosity, fear, dismay, playfulness, warnings, joy and calls to young. It has loud territorial songs as well as songs when it is excited. It moves its tongue across the lips. This may be a recognition signal, or could be used to communicate anger or curiosity. A "threat face" consists of lowering the forehead until it forms a bulge which almost covers the eyes; the lips are pushed forward and the head and neck crests are erected. This apparently is sufficient since no other body language is used.