The Virginia opossum is a confirmed resident in Maine, representing the only marsupial found in North America. This animal is a relatively recent arrival, having established a presence only in the late 20th and early 21st centuries. Their population is currently growing, though this expansion is not uniform across Maine’s diverse geography. Opossums are adapting to the northern climate.
Current Status and Geographic Range in Maine
Opossums are not yet widespread throughout Maine, with concentrations favoring the southern and coastal regions. Sightings are most common in Southern Maine counties, such as York and Cumberland, where the climate is less severe and human populations are denser. The availability of food and shelter in these areas supports their continued establishment.
The presence of stable, breeding populations significantly decreases when traveling northward away from the Atlantic coast. While individuals have been observed as far north as the Bangor region, these are typically transient individuals at the edge of the species’ current range. Biologists do not consider populations north of the Augusta area to be permanently established.
Key Characteristics and Habits
The Virginia opossum is a cat-sized mammal with a distinctive appearance. It has a grayish body coat contrasted by a long, pointed, white face and hairless ears. A long, scaly, prehensile tail is a prominent feature, often used for grasping branches while climbing. This species has 50 teeth, which is more than any other land mammal in North America.
Opossums are primarily solitary and nocturnal, active between dusk and dawn while foraging. They are omnivorous and opportunistic eaters, consuming a varied diet that includes fruits, insects, small rodents, and carrion. Their grooming habits lead them to consume ticks attached to their fur, contributing to parasite control in the environment.
When severely threatened, the opossum employs an involuntary defense mechanism known as “playing possum.” This response is a catatonic state where the animal appears dead, complete with reduced breathing and a release of a foul odor. This defense can last up to four hours, often deterring predators who prefer live prey.
Factors Driving Opossum Range Expansion
The movement of the Virginia opossum into Maine results from two factors: warming winter temperatures and increasing urbanization. Opossums are poorly equipped for extreme cold, lacking the thick fur or large fat reserves of native northern animals. Historically, the severity of Maine’s winters limited their northward spread due to starvation and exposure.
Milder winters, linked to climate change, have increased the overwinter survival rate for young opossums. This allows more individuals to reproduce and push the species’ geographic boundary further north. Despite this expansion, the opossum’s vulnerability to cold is evident in northern populations, where individuals frequently suffer frostbite on their hairless ears and tails.
The expansion is also supported by the growth of suburban and urban areas. Human settlements provide consistent, concentrated food sources, such as garbage and pet food, which are vital when natural foraging is difficult. Additionally, structures like sheds, porches, and abandoned burrows offer insulated shelter that helps the opossum survive cold snaps.