Watch where you throw your pizza. City life plumping up wild mammals, Florida study says

Who’s stronger: city mouse or country mouse? According to a new study, it’s the urban rat who is fat and happy.

So don’t you go worrying about the wayward opossums, squirrels, raccoons and other mammals you see running around the streets of South Florida. Recent research by the Florida Museum of Natural History reports that four-legged city dwellers are thriving — and growing.

Researchers of the study discovered “an unexpected pattern” after analyzing body measurements of more than 100 North American species collected over 80 years: Mammals living in urban areas are “longer and heftier than their rural counterparts.”

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The recent finding is surprising because it runs counter to the theory that city animals would be getting smaller because of higher temperatures caused by “heat island effect.”

According to the EPA, urban areas are known as “heat islands,” due to the heat emitted by structures such as tall buildings and roads. About a decade ago, climate change was thought to be causing city animals to shrink — but that’s not the case, according to this most recent report.

“That wasn’t what we expected to find at all,” said Robert Guralnick, the Gainesville museum’s curator of biodiversity informatics. “Animals that like living in urban environments could have a selective advantage while other species may lose out because of the continued fragmentation of landscapes.”

Guralnick cited the abundance of food, water and shelter, plus relative lack of predators, as some reasons for the metropolitan animals’ increase in size.

But the question remains: For how long will they continue to grow?

While bigger may be better in a biological sense, the study says that “the long-term consequences of eating a diet of human food waste have yet to be determined.”