Due to inadequate thermoregulatory abilities and poorly insulated fur, Virginia opossums are ill-equipped for cold temperatures and are, thus, not found in the northern regions of the United States and Canada.
Virginia opossums are not ubiquitous throughout the United States. The species is typically found east of the Rocky Mountains and along the west coast as they are restricted by low winter temperatures and snow depth. This climatic limitation of temperature is the Virginia opossum’s only limitation.
Given their tropical beginnings, it is not surprising that these neotropically evolved individuals are ill-equipped for extreme cold, with inadequate thermoregulatory abilities and poorly insulated fur. Instead, the northward migration and survival of Virginia opossums is likely facilitated by their metabolism of fat stores, behavioral modification during extreme temperatures, and the shelter offered by human structures. However, reports of frostbite or mortality due to starvation are common for northern populations at the edge of this species’ boundaries.
Sources: (Allen, Marchinton, & MacLentz, 1985; Harmon, et al., 2005; Hoffmeister, 2002; Hossler, McAninch, & Harder, 1994; Kanda, Fuller, & Friedland, 2005; Kimble, 1997; Ladine & Kissell, Jr., 1994; McManus, 1974; McRuer & Jones, 2009; Pérez-Hernandez, R., Lew, D., & Solari, 2016; Siciliano, 2013; Weber & O’Connor, 2000; Wilemon, 2008)
Image: Adam Buzzo