The opossum, Didelphis virginiana, is one of the world’s oldest species of mammal, and the only marsupial on our continent. Marsupials are born before they are well developed, compared to other mammals, and continue their growth and development in a pouch on their mother’s abdomen. Most members of the order Marsupialia are native to Australia and South America. Structurally, they have changed little for millions of years; the opossum’s relatives date back to the Cretaceous Period, 90 million years ago. However, the opossum didn’t appear in North America until the Pleistocene Epoch, less than a million years ago.
“Opossum” is derived from the Algonquin Indian word apasum, meaning “white animal.” A creature without specialized body structure or food preference, the opossum thrives in many settings. It is found throughout Pennsylvania, and it is classified as a furbearer.