Brown Bear at the Louisville Zoo

Bear, Brown

There are numerous subspecies of the Brown Bear.
Examples Include:
Grizzly Bear (Ursus arctos horribilis)
Kodiak Bear (Ursus arctos middendorffi)
European Brown Bear (Ursus arctos arctos)
Atlas Bear (Ursus arctos crowtheri)

The Louisville Zoo is currently home to the Grizzly Bear subspecies. Latest taxonomic studies indicate that the Polar Bear is actually a subspecies of the Brown Bear.

Brown Bears are the most widespread member of the bear family. They were once found throughout Europe, Asia & North America. Populations are becoming smaller and more isolated throughout this range.

Brown Bears can be found in a wide variety of habitats, preferring wilderness areas which include river valleys, mountain forests, open meadows, dense forests, and subalpine mountains to tundra.

Size varies considerably between populations. Gender and available nutrition also determines the size of bears.
Weight: Subspecies range at maturity from 267 pounds to 858 pounds for males. Females range from 209 pounds to 451 pounds. Average weight of a male Grizzly is about 550 pounds and for females around 350 pounds.
Kodiaks and Coastal Brown bears of Alaska may weigh over 1000 pounds.
Height: Typically Brown bears will stand about 3–4 feet at the shoulder on all fours and 6–7 feet tall when standing upright.

20 to 25 years in the wild.
Into 30’s in captivity


  • Brown bears mate in early summer, but delay implantation until the mother enters the den in late fall.
  • Cubs are born in January or February while mother is in the den.
  • At birth the cubs weigh about 1 pound. Litters range from one to four cubs, with two being the average.
  • Cubs are born blind and helpless, but grow quickly on the mother’s rich milk.
  • Cubs begin leaving the den with the mother around April or May.
  • Mother Bears ferociously defend their young, especially against predatory males.
  • Cubs will stay with the mother until they are about 2–3 years old.
  • Males become sexually mature at around 8–10 years. Females reach maturity at between 4.5–7 years of age.

Brown Bears are omnivorous; the greatest portion of their diet tends to be vegetable matter. They feed on grasses, sedges, bulbs, roots, tubers, insects, small mammals, and in some areas moose, caribou and elk.


  • Brown Bears are not true hibernators, but they do slow down their metabolism and sleep through most of the winter. This slow period in their metabolic activity is often referred to as “torpor”.
  • The mother bears seek remote locations for digging and settling in their dens in the late fall.
  • During this slow period they live off their stored fat reserves.
  • Most Brown Bears are crepuscular, although they can become active at any time of the day, especially in late summer and fall.
  • During the hot summer they will seek out denser forest vegetation and scratch out a day bed to stay cool. They are powerful diggers, using their claws to seek out roots, bulbs and rodents, as well as dig their winter dens.


  • Some of the distinguishing features of brown bears are a wide, massive head. The face is dished with a long snout and they have a prominent shoulder hump. The hump is a thick mass of fat and muscle. These features help distinguish the brown bear from the black bear.
  • Coloration in Brown Bears ranges from almost white or blond to various shades of brown to almost black.
  • The Grizzly Bear gets its name from its having extra long, silver tipped hairs that stick out farther than the rest of the fur, thus giving it a “grizzled” look.
  • Due to global warming, Brown Bears are venturing into areas once occupied by polar bears and polar bears are moving into brown bear territory. Hybridization between the two groups has been seen and viable offspring suggest a closer genetic relationship than once believed to exist. Thus polar bear classification is being revisited, placing them within the same Species as the brown bears.

Grizzly Bears are considered a threatened species under the Endangered Species Act. Wildlife managers are actively working to protect those bears and their critical habitat in the lower 48. Bears, worldwide are facing a number of challenges, especially with habitat destruction and poaching.


Bears, East, Ben Crown Publishers, Inc. New York Copyright 1977