This subfamily, containing 4 genera and 32 species, is found only in the tropical forests of Central and South America. It includes the marmosets and tamarins.
Marmosets and tamarins are among the smallest primates, with head and body lengths as small as 130 mm and tails of 150 mm. Adult pygmy marmosets weigh a mere 100 grams! The face is very sparsely furred or naked. The pelage is soft and silky, and often includes characteristic tufts of hair on the head. Coloration is variable and in some cases quite striking to the human eye. Unlike many other New World primates, marmosets do not have a prehensile tail.
In form, callitrichids resemble other primates that cling vertically to trees. The forelimbs are shorter than the hind limbs, but most locomotion is quadrupedal. The hands and feet resemble those of squirrels. The thumb and big toe are not opposable. The surfaces of the hands and feet are long relative to the digits. Additionally, all of the digits except the hallux have sharp claws, not the flattened nails found in many other primates. Callitrichids use these claws to dig into the bark of trees.
Marmosets generally have triangular upper molars, and they lack the third molar found in cebids. Their dental formula is 2/2, 1/1, 3/3, 2/2 = 32. Otherwise, the skull of callitrichids resembles that of a small cebid or cercopithecid, with a large braincase, short rostrum, and large, forward-directed orbits.
Callitrichids are diurnal and live in family groups. The general pattern of association between males and females is monogamy or polyandry, a mating system where one female has more than one mate. Females produce one to three young annually. Young are often carried on the parents' backs. In species where twins are produced, the male often carries the young while the mother forages, transferring them back to their mother only long enough for the offspring to nurse. In the saddle-backed tamarin, a species where polyandry occurs, a female associates with two males only temporarily. When the young from the first litter mature and are able to help carry their siblings, the "extra" adult male is expelled from the social group.
Like most small primates, members of this family are primarily insectivorous, although small birds, fruits and seeds, and even gum or sap may be eaten at times.
Literature and references cited
Feldhamer, G. A., L. C. Drickamer, S. H. Vessey, and J. F. Merritt. 1999. Mammalogy. Adaptation, Diversity, and Ecology. WCB McGraw-Hill, Boston. xii+563pp.
Groves, C. P. 1989. A Theory of Human and Primate Evolution. Oxford Science Publications, Clarendon Press, Oxford. xii+375 pp.
Napier, J.R. and P.H. Napier. 1985. The Natural History of the Primates . The MIT Press. Cambridge, Massachusetts.
Nowak, R.M. and J.L. Paradiso. 1983. Walker's Mammals of the World, Fourth edition. John Hopkins University Press, Baltimore, London.
Szalay, F. S., and E. Dodson. 1979. Evolutionary History of the Primates. Academic Press, New York. xiv+580 pp.
Thorington, R. W., Jr., and S. Anderson. 1984. Primates. Pp. 187-216 in Anderson, S. and J. K. Jones, Jr. (eds). Orders and Families of Recent Mammals of the World. John Wiley and Sons, N.Y. xii+686 pp.
Vaughan, T. A., J. M. Ryan, N. J. Czaplewski. 2000. Mammalogy. Fourth Edition. Saunders College Publishing, Philadelphia. vii+565pp.
Wilson, D. E., and D. M. Reeder. 1993. Mammal Species of the World, A Taxonomic and Geographic Reference. 2nd edition. Smithsonian Institution Press, Washington. xviii+1206 pp.
Nancy Shefferly (author), Animal Diversity Web.
having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.
uses smells or other chemicals to communicate
animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.
having the capacity to move from one place to another.
reproduction that includes combining the genetic contribution of two individuals, a male and a female
uses touch to communicate