The marmosets // are 22 New World monkey species of the genera Callithrix, Cebuella, Callibella, and Mico. All four genera are part of the biological family Callitrichidae. The term marmoset is also used in reference to the Goeldi's marmoset, Callimico goeldii, which is closely related.
Most marmosets are about 20 centimetres (8 in) long. Relative to other monkeys, they show some apparently primitive features: they have claws rather than nails, and tactile hairs on their wrists. They lack wisdom teeth, and their brain layout seems to be relatively primitive. Their body temperature is unusually variable, changing by up to 4 °C (7 °F) in a day. Marmosets are native to South America and have been found in Bolivia, Brazil, Colombia, Ecuador, Paraguay and Peru. They have also been spotted in Central America, Mexico, and most recently, in southern Louisiana, Texas, and California . They are also raised in captivity as pets.
Species list 
- Genus Callithrix—Atlantic marmosets
- Genus Mico—Amazonian marmosets
- Rio Acari marmoset, Mico acariensis
- Manicore marmoset, Mico manicorensis
- Silvery marmoset, Mico argentata
- White marmoset, Mico leucippe
- Emilia's marmoset, Mico emiliae
- Black-headed marmoset, Mico nigriceps
- Marca's marmoset, Mico marcai
- Black-tailed marmoset, Mico melanura
- Santarem marmoset, Mico humeralifera
- Maués marmoset, Mico mauesi
- Gold-and-white marmoset, Mico chrysoleuca
- Hershkovitz's marmoset, Mico intermedia
- Satéré marmoset, Mico saterei
- Rondon's marmoset, Mico rondoni
- Genus Callibella—Roosmalens' dwarf marmoset
- Roosmalens' dwarf marmoset, Callibella humilis
- Genus Cebuella—Pygmy Marmoset
- Pygmy marmoset, Cebuella pygmaea
Marmosets are highly active, living in the upper canopy of forest trees, and feeding on insects, fruit and leaves. They have long lower incisors, which allow them to chew holes in tree trunks and branches to harvest the gum inside; some species are specialised feeders on gum..
Marmosets live in family groups of three to 15, consisting of one to two breeding females, an unrelated male, their offspring and occasionally extended family members and unrelated individuals. Their mating systems are highly variable and can include monogamy, polygyny and occasionally polyandry. In most species, fraternal twins are usually born, but triplets are not unknown. Like other callitrichines, marmosets are characterized by a high degree of cooperative care of the young and some food sharing and tolerated theft. Adult males, females other than the mother, and older offspring, participate in carrying infants. Most groups scent mark and defend the edges of their ranges, but it is unclear if they are truly territorial, as group home ranges greatly overlap.
The favorite food of marmosets is carbohydrate-rich tree sap, which they reach by gnawing holes in trunks. Their territories are centered on the trees that they regularly exploit in this way. The smaller marmosets venture into the very top of forest canopies to hunt insects that are abundant there .
Human cultural references 
The monkey is mentioned in Shakespeare's Tempest, when Caliban says he will instruct his new master Stephano "how to snare the nimble marmoset" [for eating], on the no-man island where the play takes place (Act 2, Scene 2).
- Groves, C. P. (2005). In Wilson, D. E.; Reeder, D. M. Mammal Species of the World (3rd ed.). Baltimore: Johns Hopkins University Press. pp. 129–133. OCLC 62265494. ISBN 0-801-88221-4.
- Rylands AB and Mittermeier RA (2009). "The Diversity of the New World Primates (Platyrrhini)". In Garber PA, Estrada A, Bicca-Marques JC, Heymann EW, Strier KB. South American Primates: Comparative Perspectives in the Study of Behavior, Ecology, and Conservation. Springer. pp. 23–54. ISBN 978-0-387-78704-6.
- Stafford, S.G. (1999). "Thermoregulatory and Endocrine Adaptations of Small Body Size in Primates". Kent State University Dissertation, QP 135.S73, 1999.
- [Primate Info Net, Callithrix Factsheet, University of Wisconsin, Madison.]
- Ross, C.N., French, J.A., and Ortí, G. (2007). "Germ-line chimerism and paternal care in marmosets (Callithrix kuhlii)". Proc. Natl. Acad. Sci. USA 104 (15): 6278. doi:10.1073/pnas.0607426104. PMC 1851065. PMID 17389380.
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