The Virginia Opossum (Didelphis virginiana) is a unique creature in North America, holding the distinction of being the continent’s only native marsupial. This mammal, often mistakenly referred to as a “possum,” is recognized for its gray fur, pointed snout, and long, hairless tail. While often associated with warmer climates, their range has expanded significantly north and west, prompting questions about their presence in places like Colorado.
The Definitive Answer: Opossum Presence in Colorado
The Virginia Opossum is established in Colorado, though its presence is a relatively recent development in the state’s wildlife history. The species was first formally recorded in the southeastern corner of Colorado in 1903, marking the beginning of its westward expansion. This movement was facilitated by environmental changes, such as the planting of trees by settlers and the control of prairie fires, which created suitable woodland habitats along river corridors. The opossum’s ability to thrive near human development has allowed it to successfully colonize new territory. The current population is the result of a steady, natural range expansion that has been ongoing for over a century.
Where They Roam: Habitat and Range
The opossum’s range in Colorado is restricted to the eastern two-fifths of the state, avoiding the high elevations of the Rocky Mountains. They are primarily found across the Eastern Plains and within the urbanized Front Range corridor, including the Denver, Boulder, and Colorado Springs metropolitan areas. They tend to stick to lower elevations where temperatures are moderate and food sources are plentiful. Opossums prefer environments near water sources, often inhabiting riparian woodlands along major rivers like the Platte, Arikaree, and Republican. In urban settings, they den in brush piles, hollow trees, or opportunistic spots like under porches, sheds, and abandoned burrows.
Basic Biology and Behavior
Diet and Reproduction
As a nocturnal species, the Virginia Opossum is most active between dusk and dawn, relying on its keen sense of smell to navigate and locate food. They are true omnivores with a highly varied diet, consuming insects, fruits, seeds, birds’ eggs, and small vertebrates during warmer seasons. In winter, they readily scavenge on carrion and earthworms, which often draws them toward roadsides and residential areas. The opossum is the only marsupial north of Mexico. Females give birth to tiny, underdeveloped young, about the size of a honeybee, which immediately crawl into the mother’s abdominal pouch. These young, called joeys, remain attached to a nipple inside the pouch for 90 to 100 days before emerging.
Playing Possum
A well-known defense mechanism is the involuntary reaction of “playing possum,” or tonic immobility. When severely threatened, the animal collapses into a coma-like state, complete with a fixed stare, drooling, and a foul odor emitted from its anal glands. This convincing performance can last for hours and is an involuntary physiological response designed to deter predators that prefer live prey.
Coexisting with Opossums: Safety and Prevention
Rabies Risk
A common misconception is that opossums frequently carry rabies, but this is extremely rare due to a unique biological factor. The opossum maintains a lower average body temperature (typically 94 to 97 degrees Fahrenheit), which creates an inhospitable environment for the rabies virus to thrive. While they are susceptible to parasites like fleas and ticks, they are significantly less likely to carry rabies than other common mammals like raccoons or skunks.
Prevention
Opossums are generally non-aggressive, preferring to flee or feign death rather than confront a perceived threat. Homeowners can minimize encounters by removing attractants from their properties, especially at night when the animals are active.
Preventative measures include:
- Securing all outdoor garbage cans with tight-fitting lids, as opossums are drawn to easy food sources.
- Never leaving pet food and water bowls outside overnight, as these provide a reliable meal.
- Sealing off entry points beneath decks, sheds, and foundations to discourage them from taking up residence.