Marmosets (and the closely-related tamarins) are a New World primate that inhabit Central and South America (largely in the Northern, coastal, and Amazon area). They are tree dwellers and can be found in both mountain and valley terrain (though not at higher elevations). Marmosets have been kept as pets by some at least as far back as 17th century.

They are small, with fine, silky fur that can be tufted behind their ears. It can be a range from white to reddish and even toward the black end of the spectrum. Sometimes their long tails have rings. Since their tails are not prehensile, they have adapted to arboreal life with claws on all digits except for the big toe (which has a nail). They are also without opposable thumbs. Marmosets are considered quadrupedal and are able to move about at remarkable speed through the treetops.

They are diurnal and spend that time in the trees where they eat a diet of mainly fruit. They also are known to eat nectar, flowers, insects, spiders, and even small animals like frogs and lizards (the larger "food" probably eaten mainly by the larger tamarins). Some species have been seen following swarms of ants in order to eat the insects they stir up. Another "treat" is obtained by gouging the bark of trees to get at the sap and gum beneath.

Marmosets lack a rear inner molar in their jaws. Some scientists think this might mean they are a more "advanced" (a somewhat relative term in evolutionary biology) primate and evolved to a smaller size due to their diets. Some disagree.

They can weigh up to 1 kg (2.2 pounds) and sizes range from around 14 cm (6 inches) to around 25 cm (around 9-10 inches). All with a tail that can be from 25-40 cm (9 or 10 to almost 16 inches long). Tamarins tend to be a bit larger with similarly long tails.

The smallest marmoset is the Pygmy marmoset (Cebuella pygmaea). It is the smallest of the New World primates and weighs around 90 g (3 ounces). Despite its size, it can leap up to almost 5 m (16 feet). One can fit in your hand, being only 14 cm long, sans tail. While it is the smallest New World primate, it isn't the smallest in the world. That would be the Pygmy mouse lemur (Microcebus myoxinus) which weighs only about 30 g (just over an ounce) and is about 20 cm (about 8 inches) including the tail (about 6 cm or less than 2½ inches without).

They are social animals, though territorial, and live in groups from 5-15 members. Their home area can range from 25-100 acres, but each species keeps its territory in accordance with its diet (different species rarely overlap territory in the wild). The territory is marked by scent from chest and suprapubic glands.

Like other primates, marmosets groom each other as a way to rid the fur of foreign objects and pests.

Usually one female per group (the dominant one) breeds each season. She may mate with multiple males and can have up to two litters a year. Gestation typically lasts from 130-170 days. The litter generally consists of non-identical twins which will not be fully independent for about two months. Until then, the whole group helps care for the babies. In some species, the father even helps during the birth by biting through the umbilical cord and cleaning up the afterbirth. At 12-18 months, the young will will reach sexual maturity.

The lifespan of marmosets tends to be in the mid teens, though higher ages have been seen in captivity. Predators include the boa constrictor and the margay, or tiger cat, which is an excellent tree climber. Other threats to marmset populations include the deforestation of their habitat.

A few facts:

  • Some marmosets can emit sounds that are too high to be heard by the human ear.
  • The Satare Maue tribe of the Brazillian Amazon believe the monkeys to be the reincarnation of their deceased children and tame marmosets (and tamarins) are often found as pets among them. They are sometimes even carried around on their heads, the mammals helping the humans by "grooming" out head lice.
  • Supposedly the creatures were part of the inspiration for the gremlins in Roald Dahl's first published book (The Gremlins, 1943)
  • They are not called squirrel monkeys (Family: Cebidae; Saimiri sciureus) and only related to them above the family level. In fact, because squirrel monkeys can be carriers of of the herpes saimiri virus, they should not be allowed near since this virus is deadly for marmosets and tamarins and can kill one within 24 hours.

Marmosets (and tamarins) are of the family Callitrichidae. Ones with short lower canines, or "short-tusked," are marmosets, while the longer canined ("long-tusked") are tamarins. Marmosets are of two genera: Callithrix and Cebuella. The primate known as Goeldi's marmoset (Callimico goeldii) is the exception and is often considered a transitional between the marmoset-tamarins and other New World monkeys.

A list of species:

Goeldi's Marmoset (Callimico goeldii)
Rio Acari Marmoset (Callithrix acariensis)
Silvery Marmoset (Callithrix argentata)
Buffy Tufted-ear Marmoset (Callithrix aurita)
Golden-white Tassel-ear Marmoset (Callithrix chrysoleuca)
Snethlage's Marmoset (Callithrix emiliae)
Buffy-headed Marmoset (Callithrix flaviceps)
Geoffroy's Tufted-ear Marmoset (Callithrix geoffroyi)
Black-and-white Tassel-ear Marmoset (Callithrix humeralifer)
Dwarf Marmoset (Callithrix humilis)
Tassel-ear Marmoset (Callithrix intermedia)
Common Marmoset (Callithrix jacchus)
Wied's Marmoset (Callithrix kuhli)
Golden-white Bare-ear Marmoset (Callithrix leucippe)
Rio Manicore Marmoset (Callithrix manicorensis)
Rio Maues Marmoset (Callithrix mauesi)
Black-tailed Marmoset (Callithrix melanura)
Black-headed Marmoset (Callithrix nigriceps)
Black Tufted-ear Marmoset (Callithrix penicillata)
Pygmy Marmoset (Cebuella pygmaea)

(Sources:,,,,, species list from

Mar"mo*set` (?), n. [F. marmouset a grotesque figure, an ugly little boy, prob. fr. LL. marmoretum, fr. L. marmor marble. Perhaps confused with marmot. See Marble.] Zool.

Any one of numerous species of small South American monkeys of the genera Hapale and Midas, family Hapalidae. They have long soft fur, and a hairy, nonprehensile tail. They are often kept as pets. Called also squirrel monkey.


© Webster 1913.

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