Derby's woolly opossum (Caluromys derbianus), or the Central American woolly opossum, is an opossum found in deciduous and moist evergreen forests of Central America, from southern Mexico to western Ecuador and Colombia. It was first described by English naturalist George Robert Waterhouse, and named in honor of Edward Smith-Stanley, 13th Earl of Derby. Derby's woolly opossum is the largest in its genus, with a total length of 60 to 70 centimetres (24 to 28 in) and weight between 200 and 400 grams (7.1 and 14.1 oz). The coat is brown and the underside white-buff to golden-brown. The opossum is nocturnal (active mainly at night), arboreal (tree-living) and solitary. Diet consists of fruits, nectar, small invertebrates and vertebrates. The time when breeding takes place varies geographically