Easily the most common of the North American bear species, the black bear lives in 80 percent of the states in the U.S. as well as northern Mexico and throughout almost all of Canada. The name can be deceiving since a black bear may be varied shades of brown and even blond, although most have black fur with a white chest. The typical male adult is 5 to 6 feet in length and stands as high as 7 feet tall when it rears up on its back legs. Large specimens can weigh as much as 500 pounds but the average is between 200 and 300 pounds.
Once found anywhere in the U.S. where there were forests to support them the black bear now resides in woodlands and swamps where there is a limited human presence. It is estimated that there are as many as 600,000 black bears in North America. The black bear is an omnivore, eating a varied diet that ranges from insects, fish, carrion and small mammals to fruits, berries and nuts. In the wild the black bear can live as long as 25 years.
The brown bear varies in size depending on its diet. The Alaskan brown bear, also called the Kodiak bear, can attain weights of over 1,000 pounds due to its ability to catch and consume salmon during the spawning season. Grizzly bears, named for the grey hairs found in their fur that give them a "grizzled" look, can reach 1,000 pounds but most are considerably smaller. The grizzly once lived as far east as Ohio and all the way down to Mexico but now populations of grizzlies are limited to the Western states, with as few as 1,200 living in the lower 48 U.S. states. Alaska grizzly numbers are much higher, with as many as 30,000 living there. A grizzly is capable of killing animals as large as moose and elk, but is also an omnivore, eating many things to survive.
The Kodiak bear, another brown bear subspecies, lives exclusively on the Kodiak islands of Alaska and can grow as large as 1,500 pounds and stand 10 feet tall on their rear legs. Brown bears have a conspicuous hump of fat on their shoulders and larger claws than brown bears.
Polar bears are an offshoot of brown bears and are among the world's largest carnivores with some of the biggest specimens ever recorded weighing close to 2,000 pounds. This type of bear has a very abundant layer of blubber which keeps it insulated from the freezing temperatures of its habitat. The polar bear is distributed around the Arctic Circle but their numbers are threatened, with as few as 25,000 left in the wild according to the World Conservation Union. Polar bears kill and eat seals for the majority of their dietary needs but will also kill walruses, smaller mammals, and eat carrion. The polar bear spends a great deal of its time hunting on the Arctic ice and is directly threatened by changes in climate that reduce the amount of ice for it to hunt on. Although the fur of a polar bear is anywhere from white to cream colored its skin is black, which helps it absorb heat. Polar bears are excellent swimmers and have been known to be found extraordinary distance out at sea .