The North American Opossum (Didelphis virginiana) is the sole marsupial native to the continent. This description focuses on the anatomical characteristics of this common mammal, detailing the appearance of its body, face, specialized limbs, and prehensile tail for identification across its varied habitats.
Overall Size and Coat
The opossum is a medium-sized mammal, comparable to a large house cat in bulk and length, with a robust body carried low to the ground. Adult males are slightly larger than females, generally weighing between 2.1 to 2.8 kilograms, though some individuals reach up to 6 kilograms. Total length, from nose to the tip of the tail, ranges from 63 to 83 centimeters.
The pelage covering the trunk is shaggy and coarse, giving it a scruffy appearance. The typical coloration is a mottled grayish-white, though the hue varies geographically, sometimes appearing reddish, brownish, or blackish. This grayish appearance is created by a blend of short, dense underfur and long, white-tipped guard hairs.
The Head and Face
The head is triangular, tapering into a long, pointed snout. The facial fur is noticeably lighter than the body, typically a pale grayish-white that contrasts sharply with the darker body fur. This light facial mask is a reliable identification marker.
The eyes are small, dark, and bead-like, suggesting nocturnal habits. The ears are thin, black, and prominent, lacking dense fur. Because they are largely hairless, the delicate ears and snout are susceptible to frostbite in colder northern climates. The opossum possesses 50 teeth, a number greater than any other North American land mammal.
Specialized Feet and Tail
The opossum’s tail is one of its most recognizable features, often measuring nearly as long as the head and body combined. It is mostly hairless and scaly, resembling that of a rat, with fur only present near the base. This prehensile tail is adapted for grasping and wrapping around objects like tree limbs for stability.
While the tail is often used as a stabilizer, it is not strong enough to support the animal’s full weight for extended periods, despite common misconceptions. The feet are highly specialized for climbing, particularly the hind feet. Each rear foot features an opposable hallux, or big toe, which is clawless and functions much like a thumb. This adaptation allows the opossum to grasp branches firmly, aiding its movement as an adept climber.