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09-10-2021

Urban black bears may breed younger

A new study published in the Journal of Mammalogy compared black bears (Ursus americanus) living in the urban area of Asheville, North Carolina to those living in national forests in North Carolina and Virginia. 

With cooperation from local land owners, data was collected on 36 temporarily trapped black bears. The scientists radio collared female bears with special collars designed to fall off naturally to track them to their dens and determine reproductive status. The data collected was then compared to data collected in previous studies of bears in nearby forest areas.  

The researchers found that the urban female bears were bigger than female bears of the same age in forest areas. It was also found that urban bears as young as two years old were reproducing, an unexpectedly young age and significantly earlier than their forest counterparts. 

Study lead author Nick Gould, a postdoctoral researcher at North Carolina State University, says the results open up more questions.

“Some of the bears in Asheville are reproducing at a young age, and they are big. It definitely leads us, as researchers, to ask additional questions: What’s driving this kind of weight gain in young bears this early in life? Are they eating natural foods, bird seed and ornamental fruit, or feeding on residential garbage?”

The researchers looked for differences in availability of one important food source – nuts between urban and forest bear populations. The researchers didn’t look at either berries or human supplied food such as trash however.

“Interestingly, natural food production, in the form of nuts and other ‘hard mast’ food sources, did not influence cub production for urban bears,” said Dr. Gould. 

“We are left to conclude that either natural foods, in the form of soft mast like berries, or anthropogenic food sources in the form of garbage, bird seed, ornamental fruit trees or intentional feeding by people, is influencing the weight gain and early reproduction.”

This study still leaves many questions to be answered, however as an ongoing effort to inform the public about bears living nearby, it’s an important piece of knowledge that may help humans and bears to live together. 

By Zach Fitzner, Earth.com Staff Writer

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