Members of the Order Didelphimorpia (marsupials or pouched mammals) are divided into seven orders of with 19 families, 75 genera and 260 species. These animals are found throughout the Neotropics and Australasia. Most marsupials have an abdominal pouch known as a marsupium. Unlike placental mammals, marsupials are not fully developed when born and crawl into their mothers pouch where they are sheltered while they complete their development. Even with this less efficient reproductive process they have managed to hold their own against placental mammals. They can survive almost anywhere, adapting to many climates and eating any available food.
The most primitive Order, Didelphimorphia, is restricted to the Americas. These marsupials are small to medium-sized with one partially opposable thumb-like toe on each foot. Their sparsely-haired tails are long, scaly and prehensile. Most are at least partially arboreal, solitary and tend to be nocturnal. They are slow animals with low intelligence. They are primarily insectivorous or omnivorous. Only one species, the Virginia Opossum Didelphis virginiana, occurs in the southern United States.
Virginia Opossum (Didelphis virginiana)