Adult males are larger than the females. They are about the size of a cat. The Virginia Opossum is the only one that is capable of putting on large stores of fat.
Common Opossums from the gulf states are darker, often having all black ears and feet. Gray is the most common color pattern though. The black coloring is uncommon in the states north of Georgia, but is more common in the Southeastern United States and southward through Mexico to Costa Rica. The main difference between the black and the gray, is the color of the guard hairs.
Cinnamon colored opossums have been reported in the United States, but unreported in Latin America. The fur is softer because of the shorter guard hairs. Two white opossums are known. True albinos with pick eyes, ears, feet, tail, and eyelids. There is another one that has white fur but normal color skin. The genetic basis for these color variants is not known, but could be due to a dietary imbalance, parasites depleting nutrients from the opossom, etc.