Amid reports that human activities are pushing many wild species to the edge of extinction, it’s easy to miss the fact that some animal populations are expanding. Across North America, a number of species that were reduced by overhunting and loss of forested habitat in the 1800s are rebounding. This sometimes results in wildlife living near populated areas.
In a recent study, my colleagues and I analyzed one of these comeback species: American black bears (Ursus americanus). In the early 1900s, black bears were relegated to more wild parts of North America. Today, thanks to regulated hunting and forest regrowth, they have returned to about 75% of their historic North American range. An estimated 1 million black bears now roam from Mexico to Canada and Alaska.
In Massachusetts, where we worked, black bears have expanded from a small isolated population in the Berkshire Mountains to an estimated 4,500 bears across the state. Massachusetts is the third-most densely populated state in the nation, and human development is expanding, sometimes putting bears and people in close proximity to one another.
Other scholars have found that bears shift their behavior from natural areas to human-dominated ones in years when natural foods are scarce. My co-authors and I wanted to know how bears in Massachusetts were behaving around people and human activity. We found that in spring and fall, bears were altering their natural daily rhythms to move through human-developed areas at night.
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