Grizzly Bear

Ursus arctos


Domain Eukarya: The organisms part of this domain have a nucleus. Organisms can be either unicellular or multicellular. Cells part of this domain are about ten times larger than prokaryotic cells.

Kingdom Animalia: All animals are multicellular and capable of movement at some time in their life. All are heterotrophs (consume other organisms for food).

Phylum Chordata: Animals part of this phyla have a complete digestive system, notochord (a rod that fully extends when the animal is fully developed) and have an endoskeleton.

Subphylum Vertebrata: Members of this group all have a vertebrate (backbone), they get their movement from the muscles being connected to the endoskeleton and have a digestive system which includes the liver, digestive glands and pancreas.

Class Mammalia: All mammals part of this group have hair at some time in their life. They have three middle ear bones. These organisms also all produce milk by their mammary glands.

Order Carnivora: They have teeth that are designed to cut meat, thick coats of fur to keep them warm and males tend to be larger than females.

Family Ursidae: The members of this group have small, rounded ears, small eyes and a short tail. This is a small group of mostly large mammals. Also, this group is diverse and made up of a large variety of bears.

Genus: This group is only made up of black bears, brown bears and polar bears.

Species: Ursus arctos

General Description

  • Height: The average height of a grizzly bear when they are at the shoulder height is about 90 to 150 centimeters. When they are standing on their hind legs they are about 8 feet tall.
  • Length: The average length of the bear's head and body 5 2/3- 9 1/5 feet or 1.7- 2.8 meters. On average the shoulder length is 3-5 feet or 0.9- 1.5 meters. Bears have very short tails the average length of the tail is 2- 8 inches or 6- 21 centimeters.
  • Weight: The average weight for a grizzly bear can range from 80 kilograms to 660 kilograms. Male grizzlies tend to be about 1.8 times heavier than female grizzlies.
  • Color: The grizzly bear's main color is dark brown but these colors vary from cream to almost black. Grizzly bears that live in the Rocky Mountains have little tints of white on the edges of their fur. This is where we get the name Grizzly Bear because the tint of white gives the bear a grizzled appearance.
  • Natural Range: Grizzly Bears are normally found in North America, Alaska and Canada. But they can also be found in a few places in Europe.
  • Diet: Grizzly bears are omnivores which means they eat plants and animals. Normally what the bear eats depends on the season and how easily they can find the food. In summer the bear eats fruits, nuts, berries, bulbs, and tubers (this food can also be found during early autumn). In the fall when the bears are getting ready to be in a dormant state, larvae is an important source of protein. In Canada, most bears are carnivores or meat eaters.
  • Habitat Description: The main requirements for a grizzly bear habitat is that the area has to dense so they can shelter each day. Grizzly bears prefer areas in North America where there is a lot of space. Some common habitats in North America are desert edges, high mountain forests, ice fields (snowy fields), tundra, alpine meadows, or coastlines. In Siberia, grizzlies tend to like forests whereas in European areas, the bears are limited to the mountain woodlands.
  • Predators: Because of the bears big size they don't really have many predators except for humans. It's possible baby bear cubs can have predators such as tigers, wolves, or mountain lions. It's also possible that the bear can be attacked by other bears.

Physical Adaptations

The grizzly bear has a wet nose called the rhinarium. This gives the bear a better sense of smell and makes it easier for them to find food. These bears also have guard hairs. These hairs are the topcoat of fur and help to keep the bears undercoat dry after a swim. Grizzlies have a thick coat of fur and a layer of fat which keeps them warm in the winter. The bear's particular shoulder hump helps them keep a good balance and defend themselves from humans. Grizzlies have very powerful front legs and claws. These strong limbs and claws help the bear dig out dens in the winter. The claws also help the bear mark their territory so they can find their home faster. The grizzly bear is cryptic; this means they can camouflage which helps the bear hide from humans.

Behavioral Adaptations

When grizzly bears enter their dormant state (period of deep sleep) they find a den, cave, crevice (wall) or a hollow log. This helps the bears stay safe from danger and weather during this sleepy state. When female bears are expecting, they rest in a den or cave. This helps the baby bear cub become more healthy. Grizzlies are terricolous; this means they live on the ground. This may help the bear find food and be safe in the habitats they are used to. Grizzlies are also crepuscular which means they find food at dawn or dusk. This makes the grizzly feel more secure when leaving their cubs alone when finding food because they know there won't be many predators out. Grizzly bears are territorial which means they defend their home range in packs or by themselves. This skill helps the grizzlies with keeping their home free of danger.


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