FaunaHub

Marmoset (Callithrix jacchus)

MammalPrimateSouth America

Common marmoset (Callithrix jacchus), a tiny monkey with white ear tufts.

Common marmoset (Callithrix jacchus), Rio de Janeiro.

Image: Aatu Dorochenko, CC BY-SA 4.0, via Wikimedia Commons.

Overview

Marmosets are tiny New World monkeys of the family Callitrichidae, native to South America. The common marmoset (Callithrix jacchus), shown here, is a familiar example, with conspicuous white ear tufts and a long banded tail. Among the smallest monkeys in the world, marmosets are quick, agile, and highly social, scampering through trees more like squirrels than like larger primates.

They have an unusual diet specialisation and an unusual family life: marmosets gnaw holes in bark to feed on tree gum, and they typically raise twins with help from the whole group.

Note: “marmoset” covers several species; details here use the common marmoset as a reference. Treat general statements as approximate and verify against authoritative sources.

Habitat & Range

Marmosets live in the forests, woodlands, and scrub of South America, especially in Brazil. The common marmoset inhabits forest edges, secondary growth, and even parks and gardens in parts of eastern Brazil, and is adaptable to disturbed and urban-edge habitats where suitable trees are present.

Diet

Marmosets are specialised gum-feeders (gummivores): they have chisel-like lower front teeth that they use to gnaw holes in bark, then return to lap up the gum and sap that flows out. They round out their diet with fruit, nectar, insects, spiders, and small animals. This gum-gnawing ability sets them apart from most other monkeys.

Behavior

Marmosets live in cooperative family groups and are notable for their breeding: females usually give birth to non-identical twins, and care is shared — the father and other group members help carry and rear the infants, handing them back to the mother only to nurse. Marmosets communicate with high-pitched calls and scent marks, and they are active, fast-moving, and claw-equipped (rather than nailed) for gripping bark.

Human Interaction & Conservation

Common marmosets are adaptable and remain widespread, and they are also used in biomedical research and, unfortunately, kept as exotic pets in some places — which is restricted or discouraged because their social and dietary needs are hard to meet. Some other marmoset relatives are far rarer. Consult authoritative sources for species-specific status.

More photos of the marmoset

A common marmoset perched, showing its small size and tufted ears.

Common marmoset (Callithrix jacchus).

Image: Matheysil, CC BY-SA 4.0, via Wikimedia Commons.

Frequently Asked Questions — Marmoset

How small are marmosets?
Very small — marmosets are among the tiniest monkeys, with the common marmoset's body only around 20 cm long (plus a longer tail). The related pygmy marmoset is the smallest monkey of all. Their small size lets them exploit slender branches and feed in ways larger primates cannot.
Why do marmosets gnaw on trees?
Marmosets are gum specialists. They use sharp, chisel-like lower front teeth to gouge holes in bark, then come back to feed on the gum and sap that seeps out. This gum-feeding (gummivory) is a defining habit of marmosets and lets them rely on a food source most monkeys can't use.
Do marmosets really have twins?
Usually, yes. Common marmosets typically give birth to non-identical twins, which is unusual among primates. Raising two infants is demanding, so care is shared across the family group — fathers and older siblings help carry the babies, returning them to the mother mainly to nurse.
Do marmosets make good pets?
Not really. Marmosets are highly social, have specialised diets (including tree gum), and live a long time, so their needs are very hard to meet in a home — and keeping them is restricted or illegal in many places. This profile focuses on the wild animal; expert, ethical care and local laws should guide any decision.

Sources and further reading

Authoritative wildlife references used for general educational context. Conservation status should always be verified against current IUCN Red List data. External links open in a new tab.