Cooperative Fish and Wildlife Research Units Program: Massachusetts
Education, Research and Technical Assistance for Managing Our Natural Resources

Limitations to the distribution of a species are poorly understood, though this information is critical to understanding the abundance and distribution of organisms. We examined the biophysical limits to the northernmost distribution of Virginia opossums, by examining conditions near Amherst, Massachusetts, where opossums recently expanded their range. In combination with energetic modeling, we have shown that opossums are only able to exist in the Amherst region if they are near human developments where the microclimate is moderated, and food availability is increased. Our findings are useful in understanding how opossums have been able to successfully expand their range as far north as Canada, and have applications to predicting range expansions under global warming scenarios.