The brown bear (Ursus arctos) is native to parts of northern Eurasia and North America. Its conservation
status is currently Least Concern.
There are many subspecies within the brown bear
species, including the
Atlas bear and the Himalayan brown bear.
Brown bears are not always completely brown. Some can be reddish or yellowish. They have very large, curved claws and huge paws. Male brown bears are often 30% larger than female brown bears. They can range from 5 feet to 9 feet from head to toe.
Some countries with smaller brown bear populations include Armenia, Belarus, Bulgaria, China, Finland, France, Greece, India, Japan, Nepal, Poland, Romania, Slovenia, Turkmenistan, and Uzbekistan.
Like most animals, bears are constantly looking for food and will spend up to eight hours a day foraging. They’re vegetarians for the most part, and feed primarily on berries and nuts. Black Bears are poor hunters, though they will catch fish during spawning season, and if they’re able to ambush a fawn or moose calf in the spring, they will.
In fact, the biggest threat to their survival is starvation. Bears are shy animals. Even when they’re awake, they try to avoid humans and they’re asleep for half the year, hidden away in their dens.
The females weigh, on average, between 100-150 pounds; the males between 150-180. If food supplies are good, female bears double their size over the summer, in preparation for hibernation. Males, however, are not as active during the winter, so they’re not as likely to double their size
The only time males and females get together is in June when they mate. Through a survival adaptation called “delayed implantation,” the embryo doesn’t implant in the uterus until the fall and then only if the female has gained enough body fat to see her through the winter months when she is hibernating.
In October or November, the female looks for a spot to hibernate, usually under a tree stump or log, which she lines with grass, twigs and leaves. In January, she gives birth, typically to one or two cubs. The cubs nurse while she continues to doze periodically, and when they all emerge in April or May, the cubs have grown to weigh around five pounds each. The cubs stay with their mother all summer and hibernate with her over the winter. The following spring, she pushes them out of the den to be on their own.
When bears hibernate, their body temperature drops from 38ºC to 33ºC, and their heart rate goes from 50 beats a minute to 10. They don’t eat, drink, urinate or defecate. Hibernating bears lose at least half their body fat, but they don’t lose any muscle mass or much calcium from their bones.