Brown Bear | San Diego Zoo Animals & Plants

Shades of brown. Brown bears are brown, right? Well, maybe. They come in all sizes and shades, from a light cream color to almost black. It was once thought that there were 86 different kinds of grizzlies and brown bears in North America alone. Today, scientists agree that there is only one species of brown bear with a lot of variations (or subspecies).

Bears found in parts of coastal Alaska are called Kodiak or Alaskan brown bears and tend to be the largest. This is from eating salmon rich in fat every summer. The Alaskan peninsular brown bear has a much smaller range: just the western tip of the Alaskan peninsula. Brown bears in interior North America are known as grizzly bears because their brown fur is tipped with white or tan; the word "grizzly” means "sprinkled or streaked with gray."

There are several brown bear subspecies found in Europe, Asia, and the Middle East, but they are smaller than their North American relatives and their numbers are currently so low that their populations are at critical risk.

Get your bearings. All bears have short, thick limbs, a big, heavily built body, and a large head. Look carefully and you’ll notice that most bears walk pigeon-toed, with their feet turned inward. It makes them look a little clumsy when they’re walking, but don’t be fooled—bears can move much more quickly than most people realize. Adult brown bears are not quite as comfortable in trees as their panda, black, sun, and sloth bear relatives, although brown bear cubs are encouraged to climb for safety.

Brown bears have a large hump of muscle on top of their shoulders, and grizzly bears have the most distinctive hump of all. Their great front claws make all brown bears powerful diggers. They may build a shallow bed on the ground made of leaf litter. When the weather cools, they seek out large, cozy dens for their winter home. A den can be a rock cave, a tree hollow, a pile of brush, or a den made by digging into a hillside or under tree roots.

Snooze news. Brown bears can spend four to six months a year curled up deep in sleep, in a den. That's one-third to one-half of their lifetime! This sleep is commonly called hibernation, but unlike true hibernation, the bears' body temperature does not drop drastically. However, the bears' heart rate slows from 70 beats per minute to only 10 beats per minute, their metabolism slows, and they do not urinate or defecate all winter!

This "winter sleep" allows the bears to stay alive for a long period of time when there is little or no food available to them. Bears in warmer climates spend less of their time curled up in their dens than those in areas with a longer winter. In fact, the brown bears at the San Diego Zoo stay active year round!

Bears are the only mammals that do not pee or poop for the entire time they are in their winter sleep! In fact, by studying the way bears recycle urine, doctors have been able to help human patients with kidney failure.