Callitrichidae: Marmoset and Tamarin Family

Marmosets and tamarins make up 1 of the 2 families of primates that occur in the New World. Together with the monkeys, family Cebidae, they are known as the flat-nosed, or platyrrhine, monkeys. There are about 20 species of marmoset and tamarin, but more may sometimes be listed, depending on whether some variations are regarded as subspecies or species in their own right. Apart from the mouse-lemurs, marmosets are the smallest primates, varying from mouse-size to squirrel-size. Their fur is soft, often silky, and many have tufts or ruffs of fur on their heads. Their tails are furry and are not prehensile.

Active in the daytime, marmosets and tamarins are primarily tree-dwelling but do not have grasping hands or opposable thumbs like most primates. Neither do they swing from branch to branch, but they are rapid and agile in their movements and bound swiftly through the trees in a similar manner to squirrels. Their diet is varied, including both plant and animal material.

At night, marmosets sleep curled up in holes in trees. They are social animals and live in small family groups. The usual number of young is 2, and the male assists his mate by carrying one of the twins on his back. Often extremely vocal, marmosets make a variety of high-pitched cries.

Silvery Marmoset

This marmoset can be recognized by its silky, silvery white body fur. It has no hair on its face and ears, which are reddish in color. There is often some gray on its back, and its tail is black.

Silky marmosets have an unique jaw shape that ends in a sharp tip, and shorter canines than other marmosets and New World monkeys. This is believed to be an adaptation to feeding on exudates (gums, resins and sap) from trees. Exudates are low in protein, so the marmoset supplements its diet with fruits, leaves and insects.

Silvery marmosets live in rainforests of the Amazon Delta. They are active by day, and rarely descend from the tree tops. They rest in hollow trees or thick tangles of vines. Like other marmosets, they have claws rather than nails, which they use to grip tree trunks while climbing.

The silvery marmoset is one of the smallest monkeys in the Americas. Some silvery marmosets are brown rather than silver. These monkeys have hairless ears and faces, and their alternative name is bare-eared marmosets.

With quick, jerky movements, the silvery marmoset runs and hops through the trees and bushes in its habitat, looking for food such as fruit, leaves, tree exudates, insects, spiders, small birds and birds’ eggs. It usually moves in groups of 2 to 5.

Like most marmosets, it has a range of expressions, including facial grimaces and raising of the eyebrows, which are used to threaten rivals or enemies.

The female gives birth to 1 or 2 young, occasionally 3, after a gestation of 140 to 150 days. The male assists at the birth and is largely responsible for the care of the young.

Distribution: Eastern Brazil.

Habitat: Rainforest.

Food: Tree gum and sap. plus fruits, leaves and insects.

Size: 22 cm (8.5 in); 300 - 400 g (11 - 14 oz).

Maturity: 2 years.

Breeding: Twins born twice each year.

Life span: 10 years.

Status: Lower risk.

Goeldi's Marmoset

Few Goeldi’s marmosets have been seen or captured, and details of their habits are not well known. This marmoset is identified by the long mane around its head and shoulders and by the long hairs on its rump. This rare, unusual monkey of northern South America forms a separate group within the marmoset and tamarin family.

It lives in a range of forest habitats, preferring areas with a broken canopy where light filters through to the forest floor so that undergrowth can grow. This species is also often found in bamboo glades. It spends most of its time at low levels in the forest, less than 5 m (16.5 ft) above the ground. However, it will climb higher into the trees to reach ripe fruit.

Goeldi's monkeys live in troops that travel together in search of food. A troop typically covers about 2 km (1.24 miles) per day, moving in a roughly circular pattern within their territory, which may cover up to 80 hectares (720 acres). These monkeys sleep together as well, sheltering in a hollow tree or in dense undergrowth. They break up their daytime feeding trips with about three rest periods, during which they sunbathe and groom each other to remove parasites from their fur. Grooming also helps to strengthen social tics within the group. There is little contact between different troops. Strong, long-lasting pair bonds exist between males and females, and Goeldi’s marmosets usually live in family groups of parents and offspring.

Goeldi's monkey is unique among marmosets and tamarins, having six molar teeth on either side of its jaws (other marmosets have four). A cape of long hair hangs from the neck and shoulders. There are pale rings near the base of the tail and buff markings on the back of the neck. Juveniles lack the rings and the mane, and often the neck markings.

Goeldi's monkeys make their way through the forest by climbing trees and then leaping forward. It forages at all levels of the trees and bushes, searching for plant matter, such as berries, and for insects and small vertebrates. An agile animal, it walks and runs well and leaps expertly from branch to branch. Their diet consists mainly of fruits and insects, but they will occasionally jump down to the ground to catch small vertebrate prey.

The exact state of the population of this species of marmoset is uncertain, but it is known to be rare and to have a patchy, localized distribution. In recent years it has suffered badly from the destruction of large areas of forest and from illegal trapping. More information is needed on these marmosets in order to set up suitable reserves and to ensure the survival of the species.

Distribution: Southern Colombia, eastern Ecuador, eastern Peru, northern Bolivia and western Brazil.

Habitat: Broken forest with undergrowth, bamboo glades.

Food: In the wet season the diet consists of fruits, insects and small vertebrates such as frogs and snakes.

Size: 21 - 31 cm (8.5 - 12 in); 390 - 860 g (13.75 - 30.25 oz).

Maturity: 14 months.

Breeding: Single offspring produced each time, but females sometimes breed twice per year.

Life span: 10 years.

Status: Vulnerable.