Alaskan brown bears are the largest of all bears, growing up to 11 feet long. Their long shaggy fur keeps them warm in the cold Alaskan tundra. 75% of an average bears diet consists of over 200 types of plants. The rest of their diet consists of fish, insects, elk and moose calves and other small mammals. Beginning late summer and ending in late fall they start eating 80 or 90 pounds of food and gain 3 to 6 pounds of fat a day to store up for winter hibernation.  Hibernation is a sort of sleep some animals go into during the winter months. Alaskan brown bears will dig a hole or go into a cave. The bears heart rate drops from about 60 to about 9 beats per minute, but its body temperature under goes very little change. It drops only 5 to 7 degrees Fahrenheit . They usually come out in late April or early May to look for food.

A bear's home range varies on how many nutrition sources there are in the area. The range is usually around 561 square miles. Some bears home ranges are only about 21 square miles (the ones that are near the ocean or where there are lots of fish).  Brown bears do not usually defend their territory from other bears because the home ranges overlap each other.

Most bears mating season is between late May and early July. Females usually mate with a number of males during the mating season. In a process called delayed implantation the fertilized ovum divides and floats in the uterus for about 6 months with its development stopped. After 8 weeks, and sometime around the denning, period the embryo will attach to the uterine wall. If the mother does not have enough fat stores to carry her through the winter, the embryo will be absorbed back into her body.

The cubs are usually born while the mother is in hibernation. The average number of cubs in a litter is 2 or 3. When born, the cubs are blind, hairless, toothless and about the size of a chipmunk.  A mother bears milk has over 20% fat. When the cubs are on this diet, they will be able to leave the den with their mother when she comes out of hibernation.
 
 

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