Once the winter sets in many people in New Jersey think they don’t have to worry about black bears because they’re all hibernating. Contrary to popular opinion, black bears don’t hibernate in the Garden State, they torpor and there’s a big difference.

Black bear cub
Black bear cub (photographybyJHWilliams, ThinkStock)

“Black bears in New Jersey aren’t true hibernators. They will stay active all winter long if there's abundant food available and we have quite a few bears that you’ll see active in January, February and even with the winter that we had last year,” said Dave Chanda, director of the New Jersey Division of Fish and Wildlife.

Typically, female bears that are going to give birth the next year head into a den sometime around Thanksgiving and most of the other bears follow in December depending on the weather, but you can find active bears year-round, Chanda explained.

So what does it mean when bears torpor?

The definition of torpor is a state of lowered physiological activity typically characterized by reduced metabolism, heart rate, respiration and body temperature that occurs in varying degrees.

“A bear has a unique physiology,” Chanda said. “It slows down its metabolism. It doesn’t feed, but it is completely aware of what’s going on around it so if you were to encounter a bear denned up in the wintertime it will become active immediately. An animal that hibernates, that animal is to the point that you could go in and it’s not going to even know you were around it.”

Chanda said there is currently a lot of research underway to figure out how a black bear is able to torpor.

Chanda said it’s amazing to think that a female black bear that is going to give birth goes into a den all winter long, doesn’t feed, slows down her system, shuts down her kidneys and yet she gives birth to healthy cubs.

“If you’re out in the woods, a lot of times people probably don’t even know they disturbed a bear because there are many that just kind of nest right on the ground or they’re in a blow down of trees that are blown over and they actually hear you coming, hiking through the woods, and they literally move out of that spot before you get anywhere near them,” Chanda explained.

Once they move, they normally just look for another spot to settle in, according to Chanda, adding that bears don't have what’s called "den fidelity." He said they rarely go back to the same spot each year when they go into a winter den.

There have been bear sightings in all 21 of New Jersey's counties. It's estimated that there are about 3,600 bears in New Jersey.

To learn more about black bears, click here.

Kevin McArdle has covered the State House for New Jersey 101.5 news since 2002. Contact him at kevin.mcardle@townsquaremedia.com. Follow him on twitter at @kevinmcardle1.

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