Size: Head and body length; 20 cm. Tail length; 29 cm. Weight; Female weight; 190g, male weight; 230- 350g.

Habitat and Distribution: This marmoset is found only in small fragments of Atlantic lowland tropical rainforest in eastern and central Brazil.

Age: 10 in the wild, up to 17 years in captivity.

Groups and Breeding: The Geoffroy’s Marmoset is a social animal living in groups of 8-10 individuals consisting of a dominant female, her mate and their offspring. Only this dominant pair will breed and the young will remain with the group as adults and help care for their siblings. They in turn get breeding experience which can be put to use once a habitat becomes available for them to form their own territory.
The dominant female matures at around 15-18 months and will usually give birth to twins (although singletons and triplets do occur) after a gestation of 140- 148 days.

Diet: Plant gums, saps, nectar, fruit, insects, invertebrates and other small animals.

• Dominant female Geoffroy’s Marmosets produce pheromones in their scent gland which prevent other females in the group from ovulating and therefore breeding whilst they remain in the group.
• The father alone carries his young for the first two weeks of their life after which the whole group will take turns to carry them.
• Groups of Geoffroy’s Marmosets have been known to follow swarms of army ants as they often flush other animals, usually found further down the trees, up into the marmosets’ territory.
• This species particularly likes tree sap and has incisor teeth that are specially shaped to allow them to carve small holes in the trunks of trees, from which they drink the tree sap and gum that oozes out.
• These marmosets will mark their favourite sap/gum holes with scent markers to alert other groups in the area of their presence.
• A litter of baby marmosets weighs around 20% of the mother’s weight. This is the equivalent of a human giving birth to twins weighing 5.5kg/ 12 lbs EACH!