Grizzlies Return
DB: This is Earth and Sky. Grizzly bears used to visit the American prairies each spring – to fatten up and gain strength after a hard winter.
JB: But there haven’t been grizzlies on the plains for almost a hundred years. As more people settled the west, bears were pursued and killed. Grizzlies were more vulnerable in open areas, so they survived mainly in forests.
DB: But, since the late 1980s, bears are returning to the American prairies. Thanks to a grizzly bear recovery program, grizzly populations are expanding in some areas, and bears are moving back to some of their native prairie habitats. Of course, the prairie today is very different from that of a hundred years ago. Missing are some key foods for grizzlies – enormous herds of bison, as well as elk and bighorn sheep – replaced by domestic cattle.
JB: Roads, houses, livestock corrals and fields of grain have replaced the thousands of acres of native grass and berry-producing shrubs where bears once found food. Today’s prairie bears feed mostly on dead livestock and what berries they can find. Some bears get into conflicts by killing livestock or raiding people’s beehives or gardens.
DB: The successful bears have learned to stay away from people – and to be active in the night to avoid being seen. That’s our show – special thanks to the National Fish and Wildlife Foundation, and to the U.S. Forest Service. We’re Block and Byrd for Earth and Sky.
The following individual was interviewed for today’s show. Our thanks to:
Christopher Servheen, Ph.D.
Grizzly Bear Recovery Coordinator
U.S. Fish and Wildlife Service
University of Montana
Missoula, Montana
The following books, articles and web sites were used in preparing this script:
Canadian Wildlife Service: Grizzly
The Bear Den: Brown and Grizzly Bears
Author’s Notes:
Bears hunt for food using an acute sense of hearing and an extremely keen sense of smell-some can detect odors from more than a mile away. Bear eyesight is probably similar in acuity (sharpness) to human vision Contrary to popular belief, grizzlies are not true hibernators. True hibernation requires a significant drop in body temperature and respiration rate, whereas the grizzly’s body temperature drops only a few degrees and its respiration rate is only slightly below normal. Also, true hibernating animals, such as ground squirrels, fall into a deep winter sleep, but grizzlies, like black bears, do not. At most they are lethargic and can even be active all winter.
In areas of Montana along the Rocky Mountain Front on the east side of Glacier National Park and the Bob Marshall Wilderness Complex, as well as along the eastern edge of the Yellowstone ecosystem in northwest Wyoming, grizzly bears are reoccupying historic prairie habitats.
The fact that we have grizzlies on the prairies today indicates that they are adapting and can still live in these areas even with the human-induced changes that have occurred.
Bison was probably a key food due to the huge biomass of bison on the prairie and the availability of bison carrion, and of injured or sick animals vulnerable to bear predation.
It started in the late 1980’s, along the Rocky Mountains Front in Montana and since the mid to late-1990s along the eastern edge of the Yellowstone ecosystem in northwest Wyoming. The grizzly bear recovery program has helped increase the numbers grizzly bears in Yellowstone ecosystem and in areas of Montana.
Additional Teacher Resources
National Park Service. Bering Land Bridge National Preserve: Grizzly Bears-
A brief overview on the natural history of the grizzly, as well as habitat and social behavior.
USDA Forest Service: Bear Country
Retired U.S. Army General H. Norman Schwarzkopf leads you through an overview of the North American Grizzly Bear, covering material on bear characteristics, eating habits, hibernation, reproduction, grizzly recovery, research, management and more.
USDA Forest Service: Grizzly Bear Recovery
The Grizzly Bear once numbered more that 50,000 and roamed the prairies, forests, shorelines, and foothills from the Great Plains to the California Coast and south to Mexico. Now there are fewer than 1,100 grizzlies remaining in less than 2% of their original habitat. This report explains the decline of the grizzly and its gradual recovery.
U.S. Fish & Wildlife Service, Endangered Species Program: Grizzly Bear Recovery
When Lewis and Clark explored the West in the early 1800s, an estimated 50,000 grizzly roamed between the Pacific Ocean and the Great Plains. But when pioneers moved in, bears were persecuted and their range drastically declined. Today with the United States inhabited by more and more Americans, only a few small corners of grizzly country remain, supporting about 1,200 wild grizzly bears.
U.S. Geological Survey: Grizzly Bears
A lengthy report on the status and trends of the grizzly bear in the western United States since the mid-1800s.
