About Philander opossum (Linnaeus, 1758)
This species gets its common name from the sharply defined white spot located above each of its eyes. Its prehensile tail is two-toned: the distal section (farther from the body) is pale, while the longer proximal section (closer to the body) is darker gray, and the end of the tail is hairless. The fur on its back is gray, while the fur on its belly, throat, and cheeks is cream-colored. In adults, the ears are black except for their base. Wild gray four-eyed opossums weigh between 200 and 674 grams (7.1 to 23.8 oz), while captive individuals can weigh up to 1.5 kilograms (3.3 lb). Head-and-body length ranges from 22.0 to 33.1 centimetres (8.7 to 13.0 in), and the tail falls in a similar size range, measuring 19.5 to 35.5 centimetres (7.7 to 14.0 in).
This species lives throughout the Guianas and eastern Amazonia, specifically in Guyana, Suriname, French Guiana, and Brazil. In Brazil, it occurs east of the Rio Negro and Rio Madeira rivers. It may also be present in Venezuela.
Little is currently known about the mating habits of the gray four-eyed opossum. Because it belongs to the family Didelphidae, it is most likely polygynous, meaning males compete with one another for mates. Didelphids do not perform courtship displays, and do not form permanent pair bonds. Reproduction is typically seasonal, with more young born during the rainy season when fruit is abundant. Fewer young are born during the dry season, due to a lack of available fruit. Average litter sizes range between four and five young, and each female produces between two and four litters per year. Many young die while nursing in their mother's pouch, and this death rate is especially high during the dry season. A mother's age is a major factor that determines young survival: many young die when the mother is less than 11 months old. The average gestation period for the gray four-eyed opossum is 13 to 14 days, and each newborn weighs about 9 grams (0.32 oz). Young nurse in the mother's pouch until they are 68 to 75 days old. After weaning, they remain in their mother's nest for an additional 8 to 15 days, before the mother becomes aggressive and expels them.
