Dinos Ads

When Do Black Bears Hibernate

A black bear may consume up to 20,000 calories per day in plants, grasses, berries, acorns, insects, honey, bird seed, and rubbish throughout spring and summer.

They will hibernate in their winter caves when the weather turns cold, and the food supply runs low. So, when do black bears hibernate? Males hibernate in mid-December and emerge in mid-March, whereas females give birth in the winter, stay with their cubs for two years, and stay in their dens longer, from late November to mid-April.

Do bears hibernate?

As to whether bears hibernate or not, some scientists prefer to call it “lethargy” or “tongue-in-cheek slumber.” True or profound hibernators like rats and bats fall to near-ambient temperatures, and their metabolic rates plunge to nearly nothing within a few hours after hibernation. A few species, like the chipmunk, wake up every few hours to feed and defecate; others, like the bat, go without food for the whole winter. The bear, on the other hand, slumbers only sporadically. Its metabolism slows, and its core temperature reduces, but if disturbed or if the weather is hot, it will awaken.

You can find bear dens in specific places, including:

  • Slopes or rock crevices
  • Hollow trees
  • Beneath brush piles or dead trees
  • Open portions of the forest floor

Considering where they hibernate, this light slumber is likely a survival strategy. Beware, midwinter travelers, since sleeping bears seem to be able to feel the approach of intruders and are adept at waking up to protect themselves.

How do the black bears manage to go without feeding

The bear does not eat or drink anything for months at a time and does not urinate or defecate. This would cause muscular atrophy and bone fragility even if humans could live without food for an extended period. Remarkably, while a bear may lose up to 30% of its body weight over a vast winter, it may finish with greater muscle mass and bone density than it had at the outset.

 When fat is broken down, the body may utilize the nitrogen in urea as a source of protein synthesis to keep the bear’s muscles and organs healthy. In addition, it keeps itself hydrated and avoids renal failure throughout winter by recycling its water. Hibernation causes a bear’s blood cholesterol levels to double, but it doesn’t seem to suffer the same health consequences as a person would (atherosclerosis, gallstones). The bear’s intestines continue to generate excrement throughout the winter, necessitating a springtime search for plants with laxative properties as the sole drawback to this self-contained system.


A fetus conceived by a summer mating may only be implanted in the uterus of the mother bear after her denting if she has adequate fat reserves. She gives birth to one to three cubs in midwinter, six to eight weeks later. Only a few mammalian species have offspring that are so little in contrast to their parents as to give rise to the traditional notion that bear cubs are born dead and must be licked into form and life by their mothers. No other northern animal gives birth at such a difficult time of year. The mother sleeps intermittently for the remainder of the winter while her pups eat, develop, and await spring.

Comments are closed.