The common question of whether a “possum” and an “opossum” are the same animal arises because the terms are often used interchangeably, especially in North America. They technically refer to two separate groups of marsupials. This confusion is rooted in a historical misidentification and the tendency to drop the initial ‘O’ from the North American creature’s name. Despite sharing the defining characteristic of a pouch for their young, their evolutionary paths diverged millions of years ago.
Clarifying the Geographic and Taxonomic Divide
The separation between the two groups is geographic and scientific, placing them into two distinct taxonomic orders. The term “opossum,” with the initial ‘O,’ refers exclusively to the marsupials of the Americas (order Didelphimorphia). These creatures are found throughout North, Central, and South America, representing the Western Hemisphere’s largest group of marsupials. In contrast, the term “possum,” without the ‘O,’ is reserved for the diverse marsupials native to Australia, New Guinea, and surrounding islands. These Australian species belong to the order Diprotodontia, a group that also includes kangaroos and wombats. The name was first applied to the Australian animals by an early explorer who thought they looked similar to the American opossum, creating the confusion that persists today.
Identifying the North American Opossum
The animal most familiar to residents of the United States and Canada is the Virginia Opossum (Didelphis virginiana), North America’s only native marsupial. This creature has a coarse, grayish-white coat, a pointed snout, and small, hairless ears. It possesses fifty teeth, more than any other land mammal in North America, and has opposable, clawless thumbs on its rear feet to aid in climbing.
The Virginia Opossum is famous for its involuntary defense mechanism known as “playing possum,” or tonic immobility. When severely threatened, the animal enters a catatonic state, lying motionless, drooling, and sometimes releasing a foul-smelling fluid. This reflex is not a conscious act and is intended to deter predators. As a successful opportunist, the Virginia Opossum has an omnivorous diet, consuming insects, rodents, fruits, grains, and carrion, allowing it to survive in diverse habitats, including urban areas.
Meeting the Australian Possums
The Australian possums are a diverse group, encompassing around 70 species across various families, such as the Common Brushtail Possum and the Common Ringtail Possum. Unlike their American counterpart, these marsupials generally have a softer, thicker coat of fur and a more rounded facial structure. The Brushtail Possum is identifiable by its distinctive bushy, black tail, which is prehensile and helps in navigating trees.
Australian possums are predominantly arboreal, spending most of their time in trees, and many species rely heavily on a herbivorous diet. The Ringtail Possum, for instance, primarily consumes leaves, flowers, and fruits. Australian possums do not exhibit the death-feigning reflex; instead, they rely on hissing, growling, or climbing to evade danger. Their physical features and specialized diets set them apart from the omnivorous opossum found in the Americas.