The main differences between marmosets and tamarins concerns their dentition, which is related to dietary
preferences. Marmosets use specialized lower jaws and teeth (notably canine teeth that are small and
flattened) to gnaw on the bark of trees and vines in which they dig holes. Plant sap seeps from the wounds,
and is then fed upon by the monkey. Tamarins do not dig holes and have more generalized canine teeth, which
are long and straight. Thus, small Amazon monkeys differ in details of their biology, but are generally
similar in some respects.
Most species of small Amazon monkeys weigh 100 to 600 grams (3.5 ounces to 21 ounces). The largest is not
much bigger than a squirrel. Long tassels, tufts and mustaches of hair decorate their heads, perhaps to
enable individuals of different species to distinguish each other. Unlike larger monkeys and apes, these
small monkeys have claws instead of nails. They come in a range of colors. The saddle-back tamarin
is dark brown to red, while the bare-face tamarin has white forequarters with pale brown back and
HABITAT AND DISTRIBUTION
These species and generally prefer wooded habitats with thick vegetation where insects and fruits are
abundant. However, they adapt well to disturbed area and may be locally common around villages and in
suburbs, even living in city parks. Some species are distributed widely, such as the pygmy marmoset and
saddleback tamarin, both of which are found over much of western Amazonia. Other species have very narrow
distributions, such as the golden-mantle tamarin, found only between the Napo and Curary rivers in eastern
Ecuador and Peru. However, due to the difficulty of observing these small monkeys, the ranges of most
species are not well known.
FEEDING AND DIET
Both marmosets and tamarins feed on plant exudates (sap, resin, gum) although only the marmosets actively
dig holes. The pygmy marmoset makes several small holes in a favored tree (only certain species are used)
and then will return in successive days to feed on the resin that oozes from the holes. A family group has a
number of particular trees that it visits again and again, doing the rounds during early morning or late
afternoon. Tamarins feed on sap as well, but do not make the holes, being content to steal sap from the cuts
made by marmosets. All the species are quite opportunistic eaters however, and will take insects and fruits
and even small vertebrates when these are available.
Not all species have been studied in respect of their breeding and courtship. They generally live in small
family groups led by a single breeding female. There may be a single male or several males, with a
particular species being either polyandrous or monogamous. In most cases the males will carry the young.
Females may give birth twice a year, when twins are often born. These monkeys are the only primates to
regularly give birth to more than one offspring.
The conservation status of particular callitrichid species varies widely. Some species are abundant and
widespread, such as the saddle-back tamarin, among the commonest Amazon primates. Visitors to the rainforest
have a good chance of seeing this species in the wild. A number of species are rare and of limited
distribution. Most of the species are not hunted, but they are at risk from deforestation. Endangered
species found in the Amazon include the Brazilian bare-face tamarin (S. bicolor) which has the
smallest geographic range of any Amazon monkey, restricted to a tiny strip of forest north of the Amazon
River east of the Rio Negro.