For thousands of years, grizzly bears have roamed the forests and meadows of the Rocky Mountain region, king of the hill in a territory that includes elk herds and wolf packs.
Now this mammoth omnivore - which had dwindled to a relative handful in its competition with humans - is about to test the 30-year government effort to preserve it from extinction.
Federal officials have decided that the great bear's comeback in the Yellowstone region allows them to take it off the endangered species list - a highly unusual move both in political and biological terms.
What US Interior Secretary Gale Norton calls "an extraordinary accomplishment," is the result of a lengthy and sometime contentious collaboration of federal and state agencies, Indian tribes, ranchers and developers, and environmental groups.
Among the things done to recover grizzlies: Management of trash dumps, closure of some forest roads, bear-resistant electric fences, paying ranchers to move cattle and sheep to areas where they are less likely to be attacked by bears, and reimbursing owners when stock is killed. Through it all, teams of biologists closely tracked bears, an effort that will continue.
"We have developed a detailed management and monitoring plan ... and it will continue for the long term," says Chris Servheen, grizzly bear recovery coordinator for the US Fish and Wildlife Service. "It contains strict limits on mortality, strict habitat standards, and a comprehensive monitoring system for the bears, bear habitat, and bear foods. The future of the Yellowstone grizzly bears is bright, and I say that as a grizzly bear biologist."
Officially declaring Yellowstone grizzlies no longer threatened comes at a time when the Endangered Species Act is under intense political scrutiny.
Congress is considering changes to fundamental parts of the law, including protection of critical wildlife habitat and the financial rights of property owners.
The economic impacts on farmers, ranchers, and developers have been too severe, critics say. They also contend that the law has failed to recover species headed for extinction.
Since the mid-1970s, the list of threatened or endangered species has grown to nearly 1,300 in the United States - everything from such "charismatic megafauna" as bald eagles and bighorn sheep to obscure lichens and ferns. Only a handful of listed plants and animals have recovered to the point where they could be delisted.
Supporters of the law say many more extinctions would have occurred without the federal listing and the recovery plans that listings require.
"The Endangered Species Act has been a roaring success for the grizzly bear in Yellowstone," says Jamie Rappaport Clark, executive vice president for Defenders of Wildlife and former director of the US Fish and Wildlife Service in the Clinton administration.
But she and other environmentalists worry that oil and gas development as well as logging and log road building in the northern Rockies (all of which have been increasing under the Bush administration) could undercut US grizzly protections. Government biologists have crafted 18 "Bear Management Units" in Yellowstone National Park as well as areas of Montana, Wyoming, and Idaho outside the park.
"We would love to see grizzlies taken off the Endangered Species list - when they're ready," said Louisa Willcox, director of the Natural Resources Defense Council's wild bears project. "But that can't happen if the laws protecting grizzlies are weakened, and if they lose the few remaining scraps of land that support them."
Grizzlies roam over wide areas, much of which has been impacted by highways and urban development in their historic territory. Every year, grizzlies are killed by poachers or while crossing roads.
Some environmentalists agree with the decision to remove the big bear from the endangered species listin the greater Yellowstone area.
The National Wildlife Federation, which has been involved in grizzly bear conservation efforts from the start, fully supports delisting.
The bear population in the 9,500-square-mile area has been growing by 4 to 7 percent a year for at least 15 years, resulting in a population that has tripled to more than 600 bears, the group notes.
"Studies indicate that in Yellowstone National Park, which forms the core of the Yellowstone ecosystem, bears are at the 'carry capacity' of their environment," a NWF report states. The organization, the largest environmental group in the United States, also declares that "a solid framework is in place to ensure that continued grizzly bear conservation will follow delisting," even though the proposal announced Tuesday would allow for some hunting of grizzlies in the area.