MARMOSETS, TAMARINS, AND GOELDI'S MONKEY: Callitrichidae

PHYSICAL CHARACTERISTICS

Callitrichids (cal-ih-TRICK-ids; members of the family Callitrichidae) are among the smallest primates and include the world's smallest monkey, the pygmy marmoset. They have luxurious, silky fur that ranges from the brightly colored to the more subdued black or brownish black. Some species come in several color combinations. A shock of hair may be worn on top of the head, over the nape and shoulder, or as a beard. All have claws on fingers and toes, except for the big toes. The claws are useful for vertical clinging. Non-prehensile (nongrasping) tails are long, sometimes several inches longer than the body. Most callitrichids have scent glands in different areas of their bodies.

GEOGRAPHIC RANGE

Callitrichids are found in most of South America and in Central America (Panama and Costa Rica).

HABITAT

Callitrichids occupy various habitats, including primary forests with well-developed canopies and secondary forests with dense understories. They live in open woodlands, bamboo thickets, and scrub forests, as well as forests along rivers.

DIET

Fruits, insects, and gum (a sticky substance from tree bark) make up the main diet of all callitrichids. Most also eat nectar (sweet liquid from flowering plants), lizards, tree frogs, baby birds, bird eggs, butterflies, and spiders.

BEHAVIOR AND REPRODUCTION

Callitrichids are very social animals, living in extended family groups made up of a breeding pair, their offspring, and other relatives. They are arboreal (tree-dwelling) and diurnal (active during the day). They perform mutual grooming, or looking through each other's fur to remove parasites and dirt. Only one female breeds in a family, giving birth to twins. Goeldi's monkeys are the exceptions, having single births. The father and other family members share in childrearing, taking turns carrying the infants and sharing food with them. They guard their territories, sending messages through scent marking, loud calls, body language, and facial expressions.

CALLITRICHIDS AND PEOPLE

Marmosets and tamarins are sold as pets. These animals are commonly used in medical research, especially in the United States.

COOPERATIVE PARENTING

In tamarin and marmoset groups, just one female gives birth, producing twins each time. At birth, the twins weigh as much as 25 percent of the mother's weight. Juvenile siblings and other adults help take care of the infants, sharing food after the infants are weaned from milk and guarding them against predators. Family members take turns carrying the twins, especially since there are no places to set the babies down in tree tops.

CONSERVATION STATUS

The World Conservation Union (IUCN) lists the black-faced lion tamarin and the black lion tamarin as Critically Endangered, facing an extremely high risk of extinction, because of habitat loss/degradation from logging and hunting. The pied tamarin is also classified as Critically Endangered due to human expansion into its habitat. Five species are Endangered, facing a very high risk of extinction, because of habitat loss/degradation resulting from deforestation for agriculture: the buffy tufted-ear marmoset, the buffy-headed marmoset, the golden-headed lion tamarin, the golden lion tamarin, and the cotton-top tamarin. The IUCN classifies two other species as Vulnerable, facing a high risk of extinction, due to habitat loss/degradation from logging and hunting.

COTTON-TOP TAMARIN (Saguinus oedipus):SPECIES ACCOUNTS

Physical characteristics: The cotton-top tamarin gets its name from the long, white hair that starts as a wedge at its forehead and flows all way to the nape of the neck. Black or brown fur covers the back, and white fur covers the undersides. The black face is framed in grayish fur. The arms and legs are grayish white. The long, brownish black tail helps in keeping balance when jumping and climbing. It has claws for vertical climbing, except for the big toe, which has a flat nail. It weighs about 12.4 to 15.9 ounces (350 to 450 grams) and measures 7.9 to 11 inches (20 to 28 centimeters), plus an additional 12.2 to 16.1 inches (31 to 41 centimeters) for the tail.

Geographic range: Cotton-top tamarins are found in Colombia.

Habitat: Cotton-top tamarins are found in rainforests, but prefer the tropical deciduous forests that are typically found on the edges of rainforests. They also inhabit open woodlands and dry forests.

Diet: Cotton-top tamarins eat mainly ripe fruits, insects, and spiders. They also feed on flowers, buds, young leaves, nectar, gum, tree frogs, snails, and lizards.

Behavior and reproduction: Cotton-top tamarins live in groups of three to ten individuals, consisting of a dominant pair, their offspring, and several subordinate males and females. During the day, they travel through the forest as a group foraging for food. They take long breaks for grooming sessions to remove parasites and dirt from each other's fur. Cotton-top tamarins are vocal, making long calls to contact group members or to greet other tamarin species. They scent mark territories and use body language to communicate, such as raising their head fur or nape fur when agitated.

Only the dominant pair breeds, usually having twins. Infants travel with their parents by clinging to their fur. Both parents care for the young, although fathers usually carry the young. The parents are assisted by older siblings and other group members, who also share their food with the young. Young females leave home at about eighteen months of age, while young males stay longer until they are about two years old.

Cotton-top tamarins and people: Cotton-top tamarins are popular as pets. They are used in medical research, especially in the study of colon cancer.

Conservation status: The IUCN lists the cotton-top tamarin as Endangered because of habitat loss and degradation due to deforestation for agriculture and ranching. ∎

GOELDI'S MONKEY (Callimico goeldii):SPECIES ACCOUNTS

Physical characteristics: Goeldi's monkeys have long, silky, brownish black fur, with a mane of hair covering the neck and shoulders and longer hairs on the rump. They weigh about 1.1 pounds (500 grams) and measure 8 to 9 inches (20 to 23 centimeters), with a tail length of 10 to 12 inches (25 to 30 centimeters). Unlike other callitrichids, they have thirty-six teeth instead of thirty-two, due to an extra molar on both sides of the jaws. The long tail is used for balance in traveling through the trees. They have claws, except for the large toes that have flat nails.

Geographic range: Goeldi's monkeys are found in Bolivia, Brazil, Colombia, Ecuador, and Peru.

Habitat: Goeldi's monkeys prefer secondary forests with less-developed canopy and dense bamboo grasses and shrubs. They also inhabit deciduous scrub forests.

Diet: The Goeldi's monkey's diet consists predominantly of fruits and insects. It also eats tree frogs and occasionally forages for grasshoppers, crickets, and cockroaches on the forest floor.

Behavior and reproduction: Goeldi's monkeys live in groups of two to nine individuals, made up of one to three adult males and females. During the day they travel through the forest by vertical clinging and leaping, instead of on their four feet. They communicate through a variety of vocalizations, including trills for warning signals and whistles for long-distance calls.

Each group has two breeding females, who may give birth twice a year. Unlike tamarins and marmosets who give birth to twins, Goeldi's monkeys give birth to a single young. The mother alone takes care of the newborn for almost three weeks, after which the father and other family members share in parenting. The infant is carried on the back. However, when escaping predators, animals that hunt them for food, the monkeys do not take their young with them, but hide them among vegetation. They themselves hide in the lower shrubbery. Infants become independent by the eighth week.

Goeldi's monkeys and people: Goeldi's monkeys are trapped for the pet trade.

Conservation status: The IUCN lists Goeldi's monkey as Near Threatened, meaning they are not currently threatened, but could become so, due to habitat loss and degradation from human settlements and logging. It is classified as vulnerable in Colombia because of limited populations. ∎

PYGMY MARMOSET (Cebuella pygmaea):SPECIES ACCOUNTS

Physical characteristics: The smallest of the New World primates, the pygmy marmoset weighs about 4.4 ounces (125 grams) and measures about 5 inches (13 centimeters), with another 8 inches (20 centimeters) for the tail. The fine, soft fur is brown and tinged with yellow, resulting in a grizzled look that makes it blend in with the tree branches. The fur is thicker on the head and chest, giving it a larger appearance. The orange or yellow hands and feet have claws, except for the big toes. The non-prehensile tail maintains balance when the marmoset darts through the forest. The lower jaw has chisel-shaped front teeth for gouging holes in tree barks to extract gum.

Geographic range: Pygmy marmosets are found in Bolivia, Brazil, Colombia, Ecuador, and Peru.

Habitat: Pygmy marmosets prefer forests along rivers, as well as flood-plain forests. They also occupy scrub forests.

Diet: Pygmy marmosets consume mainly tree gum, which they collect by excavating holes on tree barks with their sharp lower incisors and canines. The gum hardens when exposed to air but can be dislodged for a fresh supply. Marmosets also feed on insects, spiders, lizards, and grasshoppers.

Behavior and reproduction: Pygmy marmosets live in groups of two to nine individuals, typically an adult pair and their offspring, which may include up to four generations. Some groups may have more than one male and female, but just one breeding pair. Marmosets breed throughout the year, producing twins. The whole family shares in child care.

Pygmy marmosets are active during the day, traveling on all fours and sometimes clinging and leaping vertically. They communicate through various vocalizations, body postures, and facial expressions. They are territorial, defending their forest sites using scent gland secretions. Defense of their territory involves calls, threat displays, and chasing of intruders.

Pygmy marmosets and people: Pygmy marmosets are sometimes kept as pets.

Conservation status: The pygmy marmoset is not a threatened species. ∎

FOR MORE INFORMATION

Books:

Angier, Natalie, and Nicholas Wade, eds. "Cotton-Top Tamarins: Cooperative, Pacifist and Close to Extinct." In The Science Times Book of Mammals. New York: The Lyons Press, 1999.

Kinzey, Warren G., ed. New World Primates: Ecology, Evolution, and Behavior. New York: Aldine de Gruyter, 1997.

Napier, John R., and Prue H. Napier. The Natural History of the Primates. Cambridge, MA: The MIT Press, 1986.

Nowak, Ronald M. Walker's Primates of the World. Baltimore: The Johns Hopkins University Press, 1999.

Preston-Mafham, Rod, and Ken Preston-Mafham. Primates of the World. New York: Facts on File, Inc., 1992.

Tattersall, Ian. Primates: Lemurs, Monkeys, and You. Brookfield, CT: The Millbrook Press, 1995.

Periodicals:

Richardson, Sarah. "A Monopoly on Maternity." Discover (February 1994): 28–29.

Web sites:

Golden Lion Tamarin Conservation Program. "About Lion Tamarins." Smithsonian National Zoological Park. http://nationalzoo.si.edu/ConservationAndScience/EndangeredSpecies/GLTProgram/Tamarins/About.cfm (accessed on July 6, 2004).

Paschka, Nick, and Phil Myers, eds. "Callimico goeldii." Animal Diversity Web. http://animaldiversity.ummz.umich.edu/site/accounts/information/Callimico_goeldii.html (accessed on July 6, 2004).

"Pygmy Marmoset." Smithsonian National Zoological Park. http://natzoo.si.edu/Animals/Primates/Facts/FactSheets/PygmyMarmosets/default.cfm (accessed on July 6, 2004).