Caluromys derbianus is the largest species in the genus. It is a long, slender animal weighing from 8 - 16 ounces. The common name of this opossum is derived from its woolly pelage. A dark strip is often present running from the crown to the fleshy portion of the nose. Pelage color shows much geographic variation. Its ears are creamy white to pink. All digits of the front and hind feet are clawed with the exception of the opposable hallux. The tail constitutes up to two-thirds of its total length. The latter half of the tail is naked and prehensile. Barrington and Willis (1973) ; Bucher and Hoffmann (1980)

The woolly opossum inhabits both lowland and highland rainforests to a maximum altitude of 2,460 meters. Bucher and Hoffman (1980)

Biomes: tropical rainforest

Neotropical: Caluromys derbianus can be found in both highland and lowland rain forests in the region between south-central Veracruz, western Columbia, and northern Ecuador. Bucher and Hoffmann (1980)

Litter size for C. derbianus is usually three or four, although it may be as high as six. The woolly opossums breed during the dry season (January to June) in Central America, however a few studies indicated that breeding may extend into the first few months of the rainy season (July to September). In Nicaragua it has been suggested that they breed throughout the year. The estrous cycle has an average length of 27 to 29 days and is maintained year round. The young attach to a teat after birth (in a pouch), where they are nurtured until they reach a level of development similar to young placentals at birth. Caluromys derbianus reaches sexual maturity at seven to nine months and has been reported to live in excess of five years in captivity. Bucher and Hoffman (1980) ; Dawson (1983)

Although food habits have not been investigated thoroughly, this opossum also appears to be omnivorous. Captive animals have eaten fruit, insects, and mice. They have been maintained on a laboratory diet of raw egg, fruit, and dog food. Bucher and Hoffman (1980)

Little is known of the woolly opossums' behavior in nature. Captive animals showed a broad range of behavior initially, although any behavior was reduced dramatically once the animal was in captivity. In captivity the species is strictly nocturnal with greatest activity periods just before and after the light period. Food deprivation caused a doubling in activity level, while constant illumination resulted in a decrease in activity. Elevated temperature (23 C to 26 C) and humidity (50 to 80%) were found to be beneficial in maintaining C. derbianus . Caluromys derbianus uses its forefeet for both food manipulation and facial grooming. The forefeet are also used to groom the ventral and lateral sides; the distal portion of the tail is also held and licked. The animal is a skillful climber and uses its tail extensively for both balance and grip.

Once hunted for its fur, and possible important as a disperser of tropical trees. Bucher and Hoffman (1980)

Barrington, E. and Willis, A. 1973.
Life of Marsupials. American Elsevier Publishing Company, Inc., New York

Bucher, J. and Hoffman, R. 1980.
Mammalian Species No. 140. American Society of Mammalogists.

T. J. Dawson. 1983.
Monotremes and Marsupials: The Other Mammals. Edward Arnold Publishers Limited, London.