The grizzly (Ursus arctos) is the most widely distributed of the eight bear species; they are found in North America, Asia, and Europe. In earlier centuries, grizzlies were quite abundant. Today, there are only about 150,000 remaining, mostly in the former Soviet Union. The grizzly is almost non-existent in the lower 48 states of the U.S., where fewer than 1,000 remain.
Although some people in North America refer to those that live in interior ranges as grizzlies and those in coastal regions as brown bears, they are, in fact, the same species -- ursus arctos.
Grizzlies are very large and intimidating animals -- their claws, for example, are usually at least 3 inches long (9 cm) and often can be seen at a distance. These claws are used primarily for digging for food rather than climbing. Grizzlies stand 6-7 feet (1.8 to 2.1 m) tall (3.5 feet when they are on all fours) and can weigh from 330 to 825 pounds (150-375 kg), although females are slightly smaller. Bears generally weigh more in the late summer when they have fattened up prior to winter hibernation. Their shaggy fur ranges in color from yellowish to dark brown, sometimes approaching black. In addition, the term grizzly is a colloquial name that refers to its silvery-tipped hairs, especially on the back, that give it a "grizzled" effect.
Many people hold the misperception that the grizzly is a slow, prodding animal. Far from it! Although they can look clumsy, grizzlies can run 35 mph (56 kph) for short distances. This easily enables them to overtake most other large mammals, including humans. In addition, the grizzly remains quite active throughout the day, often covering 15 miles (25 km) or more over the course of a twenty-four hour period.
Although the grizzly bear maintains poor hearing and vision, it has a keen sense of smell, which enables it to detect food and other animals.
Although the grizzly bear is widely distributed throughout the world, it's presence has diminished substantially in the past century, primarily because of hunting. At one time, grizzlies were abundant throughout North America, even along the prairies of the United States (and even as far south as Mexico). In the 1880's, there were probably over 100,000 grizzlies in that region. Today, there are fewer than 1,000.
Grizzly distribution has decreased significantly in Europe and Asia has as well. Once populous over the entire region, including the British Isles, Japan, Siberia, North Africa, the Himalayas, and China, the bear has disappeared from most of its former range. In central Europe, grizzlies probably only number in the hundreds.
The grizzly bear is an omnivore, which means it eats both plants and animals. However, more than 75% of is die consists of vegetation. Hardly a picky consumer, the grizzly will eat over 200 varieties of plants, including flowers, grass, herbs, roots, and all kinds of nuts --it is especially fond of cranberries and pine nuts. The key for the grizzly is to find a lot of nutritious food with as little effort as possible, since it requires an enormous daily caloric intake. During peak feeding periods (e.g. summer and early fall, when they fatten up for the winter), grizzlies can eat 80 to 90 pounds (36 to 41 kg) of food per day.
Grizzlies also scavenge on animal carcass, and catch fish, insects, elk, moose, and small mammals.
Females become sexually active by the time they reach 3.5 years of age, although they generally don't produce a litter until age five or six--males begin mating between three and six years of age. Mating generally occurs between late May and early July, and both males and females will often pair with more than one partner. However, because of a fascinating process called "delayed implantation," (where the fertilized ovum remains in an arrested development stage in the uterus), the embryo will not begin developing until October or November, so that cubs may be born between January and March, when the pregnant female is in hibernation.
The number of cubs delivered will range from one to four (average two per litter). They are born blind and hairless, and weigh only 21 to 25 ounces (600 to 700 grams). These cubs will feed on their mother's milk while she hibernates. By the time the female grizzly is ready to leave the den, her cubs are ready to accompany her.
The first years of a cub's life can be dangerous, with a real threat of starvation, disease, attack by other animals (such as wolves, mountain lions, or eagles) or even infanticide. During this period, the mother will teach her cub all of life's basics, including hunting and other survival techniques. By the time a cub reaches two or three years old, they are left by the mother to fend for themselves.
Grizzlies can live in the wild for twenty-five years or even more.
During the cold months of winter, when food is scarce, bears will engage in an energy saving "activity" called hibernation. They will stop eating, build a den in a rock cave, and enter a long sleep. During the hibernation period, bears become completely inactive. Their heart rate will drop dramatically, and they will lose a tremendous amount of weight -- males can lose 15%-30% of the body weight and females as much as 40%.
Grizzlies are generally solitary animals, although they are sometimes seen in groups of 100 or more when food is abundant.
Are grizzly bears dangerous?
They can be. Although grizzlies are not particularly territorial, they are often unpredictable, which can lead to catastrophes for humans which get too close. If you ever find yourself hiking or camping near a grizzly, get away fast!
The grizzly bear is being actively protected around the world, particularly under the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), a treaty among more than 120 nations aimed at controlling illegal trade in endangered animal and plant species. In the United States, the grizzly is listed as "threatened" under the Endangered Species Act of 1973.