The MARMOSET is one of the world’s smallest primates, and is the smallest “true monkey”. The marmoset belong to the genera Callithrix.
Most marmosets are about 8in in length. Relative to other monkeys, they show some apparently primitive features : they have “claws” rather than “nails” and “tactile hairs” on their wrists. They lack wisdom teeth and their brain-layout seems to be relatively primitive. They have distinctive large white ear tufts and their tail is striped, alternate “wide dark” and “narrow pale” bands. Their coat is grey, black, brown and white with streaks of orange. Their body temperature is usually variable, changing by up to 4 degrees C in a day. They are arboreal and weigh less than a can of baked beans. Claw-like nails enable them to cling to trees.—— Originating in the Atlantic Coastal Forest in North-east Brazil, they have also been introduced in some parts of south-east Brazil, including some urban areas. They are also raised in captivity.
According to recent research, marmosets exhibit “germine chimerism”, which is not known to occur, in nature, in any other primate. 95% marmoset fraternal twins trade blood through “chorionic fusions”, making them “hematopoietic” chimeras. —— Marmosets are highly active, living in the upper canopy of forest trees and feeding on insects, fruits and leaves. They have long lower incisors, which allow them to chew holes in tree trunks and branches to harvest the “gum” inside, and some species are specialised feeders on gum.
Marmosets live in family groups of 3 to 15, consisting of 1 to 2 breeding females, an unrelated male, their offspring and, occasionally, extended family members and unrelated individuals. Their mating systems are highly variable and can include —— monogamy, polygamy and, occasional, polyandry. Adult males, females and other than the mother and older offspring participate in carrying infants. Most groups scent-mark and defend the edges of their ranges. The favourite food of the marmoset is carbohydrate-rich tree sap. Their territories are centred on the trees that they regularly exploit in this way. The smaller marmosets venture into the very top of forest canopies to hunt insects that are abundant there. They should not be kept as pets as they need expert care.
CALLITHRIX comes from ancient Greek and means “beautiful fur”. Marmoset from the French “marmouset” is of uncertain etymology. The marmoset is mentioned in Shakespeare’s TEMPEST, when Caliban says he will instruct his new mater — Stephano, “how to snare the nimble “marmoset” (for eating), on the no-man island where the play takes place (Act 2, Scene 2) Sax Rohmer’s fictional Doctor Fu Manchu, has a pet marmoset, often perched on his shoulder.