Jennifer McMonagle
Bio 378 Sect. 3
Mammology Species Account
Description:
Silvery marmosets, Callithrix argentata, are among one of the smallest “New
World” monkeys. Their total body length averages about 18 cm to 28 cm, their tail
length averages about 26 to 38 cm, and weigh between 300 and 360 grams. The species
vary in color from silvery white to dark brown, with the dark brown marmosets having
hairless ears and faces-also called bare-eared marmosets. The silvery white marmosets
are white in color with pink ears and face and a black tail. The silvery marmoset differs
from most of the other New World monkeys by possessing claws on all their toes except
their big toe. (Napier 1985)
Distribution:
Silvery marmosets are found south and east of the Amazon River in Brazil and
tend to be isolated from other marmosets with the exception of the Amazon delta; there
they co-occur with Callithrix jacchus.
Marmoset activity is mostly concentrated in areas with many gum-producing trees.
Range size is positively correlated with fruit availability and appears to be limited by the
size of the main patch of contiguous forest available to the group. (Rowe 1996)
Reproduction:
Marmosets begin to breed after they are between 15 and 18 months old. There is
typically only one breeding pair in a group where all members of the family care for the
young and from time to time they pass the babies back to their mothers for feeding.
The gestation period varies from 140-146 days. A few weeks before they give
birth their activity slows down considerably. They usually give birth to twins but
sometimes 1 or 3 young are born. (Napier 1985)
Behavior:
Silvery marmosets are mainly gumivores, in which their diets consist mostly of
sap and gum of the trees. They have very large canine teeth and incisors so they are able
to scrape large areas of trees to get at the sap and liquids of the trees. They also eat some
fruit, insects, and leaves.
Silvery marmosets use their large claws to climb trees, forage for food, and to
escape from predators. Males and females mark their paths in trees with urine so other
marmosets can follow, and to claim territory. Like other New World monkeys,
marmosets communicate somewhat vocally with a few general calls for warning and play.
Silvery marmosets also have a unique behavior that they display when they feel
threatened: they stand tall and lower their eyebrows and smack their lips. (Swindler 1998)
Ecology:
Marmosets are being threatened by the destruction of forests, but unlike many
other species, marmosets have their own way to cope with their declining food sources.
They feed off human food crops and live in smaller secondary forests. It is not known
how long this surviving strategy will continue to allow them to survive. (Mafham 1992)
Literature Cited:
Napier, J., P. Napier. 1985. The Natural History of the Primates. Cambdridge,
Massachusetts: MIT Press.
Mafham, R. 1992. Primates of the World. London, UK: Blandford Publishing.
Rowe, N. 1996. The Pictorial Guide to Living Primates. East Hampton, New York:
Pogonias Press.
Swindler, D. 1998. Introduction to the Primates. Seattle, Washington: University of
Washington Press.
Reference written by Jennifer McMonagle, Biology 378 student. Edited by Christopher Yahnke.
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