Goeldi’s Marmoset or Goeldi’s Monkey (Callimico goeldii) is a small, South American New World monkey. It lives in the upper Amazon Basin region of Bolivia, Brazil, Colombia, Ecuador, and Peru.
Goeldi’s Marmosets are blackish or blackish-brown in color. Their bodies are around 8 to 9 inches long (about 22 cm), and their tails are 10 to12 inches long (25-30 cm).
Females reach sexual maturity at 8.5 months, males at 16.5 months. The gestation period lasts from 140 to 180 days. Unlike other New World monkeys, they have the capacity to give birth twice a year. The mother carries a single baby monkey per pregnancy. Most other species in the family Cebidae usually give birth to twins. The infant is weaned after about 65 days. The life expectancy in captivity is about 10 years.
Goeldi’s Marmosets prefer to forage in dense scrubby undergrowth. Possibly because of this, they are rare, with groups living in separate patches of suitable habitat. Miles of unsuitable flora separate them. In the wet season, their diet includes fruit, insects, spiders, lizards, frogs, and snakes. In the dry season, they feed on fungi. They are the only tropical primates known to depend on this source of food. They live in small social groups (approximately six individuals) that stay within a few feet of one another most of the time. They keep contact with high-pitched calls.
The species takes its name from its discoverer, the Swiss naturalist Emil August Goeldi.