Tamarins Marmosets and Goeldi's Monkey: Callitrichidae

Physical characteristics: The smallest of the New World primates, the pygmy marmoset weighs about 4.4 ounces (125 grams) and measures about 5 inches (13 centimeters), with another 8 inches (20 centimeters) for the tail. The fine, soft fur is brown and tinged with yellow, resulting in a grizzled look that makes it blend in with the tree branches. The fur is thicker on the head and chest, giving it a larger appearance. The orange or yellow hands and feet have claws, except for the big toes. The non-prehensile tail maintains balance when the marmoset darts through the forest. The lower jaw has chisel-shaped front teeth for gouging holes in tree barks to extract gum.

The pygmy marmoset is the smallest of the New World primates. (© Art Wolfe/The National Audubon Society Collection/Photo Researchers, Inc. Reproduced by permission.)

Geographic range: Pygmy marmosets are found in Bolivia, Brazil, Colombia, Ecuador, and Peru.

Habitat: Pygmy marmosets prefer forests along rivers, as well as flood-plain forests. They also occupy scrub forests.

Diet: Pygmy marmosets consume mainly tree gum, which they collect by excavating holes on tree barks with their sharp lower incisors and canines. The gum hardens when exposed to air but can be dislodged for a fresh supply. Marmosets also feed on insects, spiders, lizards, and grasshoppers.

Behavior and reproduction: Pygmy marmosets live in groups of two to nine individuals, typically an adult pair and their offspring, which may include up to four generations. Some groups may have more than one male and female, but just one breeding pair. Marmosets breed throughout the year, producing twins. The whole family shares in child care.

Pygmy marmosets are active during the day, traveling on all fours and sometimes clinging and leaping vertically. They communicate through various vocalizations, body postures, and facial expressions. They are territorial, defending their forest sites using scent gland secretions. Defense of their territory involves calls, threat displays, and chasing of intruders.

Pygmy marmosets and people: Pygmy marmosets are sometimes kept as pets.

Conservation status: The pygmy marmoset is not a threatened species. ∎