Marmoset Monkeys

Pick up any recent text book, and consider how closely the description follows the 1855 account in Orr's circle of the sciences.

"They are all small Monkeys, about the size of a Squirrel or a little larger; their heads are rounded, and their ears usually furnished with a tuft of hair. The hind feet are provided with an opposable thumb, which bears a flat nail; but all the other fingers of both pairs of extremities are armed with sharp claws, and the thumb of the anterior members is scarcely opposable. The tail is long and usually bushy, but never adapted for prehension; and the whole body is clothed with a soft woolly fur.

These elegant little creatures are found in great abundance in the forests of Brazil, where they run about the trees in a manner very similar to that of our Squirrel, which they a good deal resemble in appearance. They feed on insects and fruits, and also on birds and their eggs; indeed they seem to be very predaceous little creatures, although they may be easily tamed, and were formerly favourite pets with fashionable ladies. There are numerous species, twenty-five or thirty being already described."

While the basic description of marmosets remains little changed, in the one hundred and fifty plus years since Orr's publication, informal and formal interest in marmosets continued almost unabated.

Callitrichines provides one of the most recent family literature reviews, including the Marmosets. The author notes a lack of extensive field studies on most group species.

Technically, the family currently breaks down into seven genera, four of which are marmosets, although the majority of marmoset species belong to either the Callithrix or Mico genera:

• Callibella: one species,
• Callithrix: Atlantic marmosets
• Cebuella: one species, the world's smallest monkey the pygmy marmoset
• Mico: Amazonian marmosets (some taxonomists suggest that Cebuells or the pygmy Amazonian marmosets be placed in a separate genera)

Marmoset behavioral studies tend to reveal some common group traits, including a sweet tooth for tree sap (gum) and fruits.

The high number of marmoset species precludes a definitive group social structure. A broad brush approach to marmoset society paints them as a gregarious, with many species cooperatively raising their young.

The top picture shows a Common Marmoset (Callithrix jacchus) one of the most wide spread of all marmoset species and a resident of Brazil's coastal Atlantic forests.

Lack of comprehensive marmoset research currently translates into inadequate population estimates. The IUCN currently lists one species, the Buffy-headed Marmoset (Callithrix flaviceps) as endangered.

© 2010 Patricia A. Michaels.