MARMOSET

any of the small, long-tailed, South American monkeys constituting the family Callitrichidae. Marmosets are squirrel-like tree dwellers and move in a quick, jerky manner. They are active during the day; live in small groups; and, as an aid to scampering along branches, have claws on all digits except the big toe. Unlike other American primates, they lack the last (third) molar teeth in both jaws. Marmosets have been kept as pets since the early 17th century, but they require some care to remain healthy. They are primarily insect eaters but take fruit as well as other small animals. The gestation period is about 145 days, and the females generally bear twins. Marmosets fall into two groups: those with short lower canines (short-tusked) are commonly called marmosets, and those with relatively long lower canines (long-tusked) are known as tamarins. Pygmy marmosets (Cebuella pygmaea) are the smallest members of the family. Their head and body are about 14 centimetres (6 inches) long, the tail somewhat longer. Adults weigh only about 90 grams (3 ounces), whereas other members of the family attain weights of up to 1 kilogram (2.2 pounds). Marmosets of the genus Callithrix are more common. These animals are about 1525 cm long, excluding their 2540-cm tails. Their fur is dense and silky and generally forms tufts on the ears. Colour varies among the eight species from white to reddish or blackish, and it may be grizzled or otherwise marked, as with rings on the tail. About 25 species of tamarins are placed in the genera Leontopithecus (Leontideus of some authorities) and Saguinus. Tamarins are about 2035 cm long, excluding the 3040-cm tail. One of the most striking forms is the golden lion tamarin or marmoset (L. rosalia), which has a thick, lionlike mane; black face; and long, silky, golden fur. Another species, the emperor tamarin (S. imperator), has long, grizzled, gray fur; a reddish tail; and long white moustaches. The three species of Leontopithecus are all listed as critically endangered in the Red Data Book. Goeldie's marmoset (Callimico goeldii) is a small, rare, black monkey of the upper Amazon. It is generally placed with the Callitrichidae (sometimes as the subfamily Callimiconinae), but certain of its features are like those of the other New World monkeys (family Cebidae). Depending on the authority, tamarins and marmosets may be placed in various different genera. (See Table.)