About Caluromys derbianus (Waterhouse, 1841)
Derby's woolly opossum is the largest species in the genus Caluromys. It has a total length of 60 to 70 centimetres (24 to 28 in) and weighs between 200 and 400 grams (7.1 to 14.1 oz). Its distinguishing features include white to pink ears, lightly coloured limbs, a brown coat that is lighter than the coat of the brown-eared woolly opossum, and a white-buff to golden-brown underside. Its prehensile tail, which can be used to grab objects, makes up 58 to 67 percent of the animal's total length. A dark stripe runs along the midline of the nose from the nose up to the crown. Coat colour varies by geographic location. Similar to the bare-tailed woolly opossum, the tail is partially naked. Like other species in the genus Caluromys, Derby's woolly opossum has a pouch. Its ears measure about 4 centimetres (1.6 in) and its hindfeet measure 3.5 centimetres (1.4 in). Claws are present on all five digits of the forefeet, and on two digits of each hindfoot. Its dental formula is 5.1.3.4 / 4.1.3.4. When exposed to light, the eyes of Derby's woolly opossum glow red. Derby's woolly opossum inhabits deciduous and moist evergreen forests up to an altitude of 2,600 metres (8,500 ft). Its range extends from Veracruz in southern Mexico, southward into South America to western Ecuador and the Cauca River valley in Colombia. The IUCN Red List classifies this species as least concern, as its population is presumed to be large. Historically, this species was hunted for its fur. Populations in Ecuador and Mexico are currently threatened by deforestation. Derby's woolly opossum is nocturnal (active mainly at night) and solitary. It spends most of the day in nests made of dead leaves, located in tree cavities in the upper reaches of trees. Research shows that its activity levels can increase when food is scarce, and decrease when exposed to light. It is an efficient climber, and its prehensile tail helps it grasp branches. It moves with remarkable agility among vines and branches. When disturbed, it may attack defensively by biting, and it can produce squeals when distressed. Ocelots are known predators of Derby's woolly opossum. Both male and female Derby's woolly opossums reach sexual maturity at 7 to 9 months of age. The estrus cycle is nearly 28 days long. Breeding time varies by geographic location: breeding occurs during the dry season in Panama (late January or early February), and likely occurs year-round in Nicaragua. Males have been observed pursuing females before copulation. Litter size ranges from one to six. The lifespan of Derby's woolly opossum in the wild is not confirmed; one individual held at New York Zoological Park lived for five years and three months.
