Didelphids

Didelphids, or opossums, constitute the Didelphidae family, the largest group of marsupials native to the Americas. With around 100 species in several genera, didelphids range from southern Canada and the United States through Central America to most of South America, occupying a wide range of habitats from tropical forests to grasslands and urban areas. The Virginia opossum (Didelphis virginiana) is the best-known North American representative.

They are small to medium-sized mammals with soft fur and a long, relatively prehensile tail used for balance and grasping branches. Most species are omnivorous and opportunistic feeders, consuming fruit, insects, small vertebrates, eggs, and carrion. Many didelphids are nocturnal and solitary, and some arboreal species display strong climbing abilities.

Reproduction in didelphids is characteristic of marsupials. Females give birth to very underdeveloped young after a short gestation; the young crawl to the teat area to continue development. In species with a well-formed pouch, several offspring attach to teats inside the pouch. In species with only a rudimentary pouch or none, the young latch onto teats on the abdomen or back. Litter sizes can be relatively large given their small size, and development continues after birth inside the nest or pouch.

Ecology and behavior: didelphids play roles as seed dispersers, insect controllers, and scavengers. They adapt well to fragmented habitats and can thrive in urban environments, though some species face threats from habitat loss and introduced predators.

Taxonomy and evolution: Didelphidae belongs to the order Didelphimorphia, an early-diverging marsupial lineage. The family includes genera such as Didelphis, Philander, Marmosa (mouse opossums), Caluromys, and Lutreolina, reflecting substantial diversity in size and habitat across the Americas.