Geoffroy's marmoset
Scientific name: Callithrix geoffroyi
Country: Brazil
Continent: South America
Diet: Fruits - frugivore, nectar - nectarivore, plant gums & saps - gummivore, insects - insectivore, small lizards and birds.
Food & feeding: Omnivore
Habitats: Tropical rainforest, tropical dry forest
Conservation status: Vulnerable
Relatives: Buffy-headed marmoset, Golden-headed lion tamarin
Description: Marmosets are small, squirrel-like primates from the Atlantic rainforests of south-east Brazil. They have 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.
Lifestyle: Marmosets are diurnal and sleep at night in tree holes or other shelters. During the day they roam around territories that may be up to five hectares in size. Each home range contains a number of favourite trees to which they return regularly to lick sap and gum, emerging from the holes that they have already carved.
Family & friends: They live in family groups of up to 10 animals, consisting of the dominant female, her mate and their offspring. The young remain in the group, even when adult, to help care for their younger siblings. These 'helpers' gain breeding experience whilst waiting for a suitable habitat to become available. The parents of larger groups have more helpers and have to spend less time carrying their young themselves.
Keeping in touch: They have overlapping home ranges, which they do not defend but register their presence using scent. Scent is often smeared around favourite gum holes in trees. Other marmosets from other neighbouring groups may use the same holes, so these trees serve as community message boards.
Growing up: The dominant female gives birth to twins after a gestation period of about 4.5 months. The birth weight of the litter is high, about 20% of the mother's weight. This would be the same as a human giving birth to twins each weighing 5 kg (11 lb)! All group members, including the father, take part in carrying the young, with the mother periodically suckling the young. Marmoset infants are completely dependent for the first two weeks but they are weaned by two months, can move independently and collect their own food. They reach puberty at 14-18 months and adult size at two years. Their lifespan is around 10 years.
Geoffroy's marmosets are one of a few species that specialise in feeding on tree sap. Humans also eat tree sap sometimes: maple syrup is the concentrated sap of the maple tree. Trees have a number of defences against attack: the trunk is covered in a thick layer of bark, which the marmosets must first bite and chew through. Once the sap is flowing, the tree tries to stop the flow by producing gums, resins and latex that seal the hole up. Marmosets must return to the holes and remove the gum (that they also eat) to start the flow of sap again.
Conservation news: Least concern. A variety of factors have contributed to their decline in the past, including: habitat destruction; persecution due to the assumption that they carried yellow fever and malaria and even exportation to zoological societies and biomedical research centres. Today, habitat destruction is their greatest threat.
