In 1975, the grizzly bear–once the undisputed king of the western wilderness–is given federal protection as a threatened species under the Endangered Species Act.

Before the Anglo-Americans began invading their territory, the grizzly bear inhabited most of the country west of the Mississippi from Mexico north to the Arctic Circle. Its only serious competitors for food were the Native Americans, who considered it a sacred animal-although they did hunt the bear as a test of strength and its long claws were prized symbols of status.

Because of the grizzly’s fearsome size and aggressive nature, most early European explorers of the West noted their encounters with the animal. During their expedition to the Pacific, Lewis and Clark encountered many of the bears and were awed by their impressive speed and power. On July 1, 1805, while the expedition was making the slow portage around the Great Falls of the Missouri River in Montana, Lewis wrote in his journal that grizzlies were all around their camp. “We have therefore determined to beat up their quarters tomorrow,” he continued, “and kill them or drive them from their haunts about this place.”

Because of such hunting and the general destruction of their habitat, the grizzly began to disappear in concert with the settlement of the West. California, which is estimated to have once been home to 10,000 grizzlies and placed the animal’s image on its state flag, no longer had any of the bears by 1924. During subsequent decades, grizzlies gradually disappeared from their native homes in Texas, Nebraska, Oklahoma, Kansas, Arizona, New Mexico, Oregon, Utah, the Dakotas, and probably Colorado and Washington. Outside of Alaska, by the 1970s small populations of bears remained only in a few isolated wilderness areas and national parks in Montana, Wyoming, and Idaho.

In a last ditch effort to halt the decline, Congress designated the grizzly a threatened species on this day in 1975. Protected from hunting and trapping, grizzly populations have slowly begun to recover. However, there are still probably fewer than 1,000 grizzlies in the lower 48 states today, nearly half of them in Glacier and Yellowstone National Parks. Recently, plans to reintroduce the species into two wilderness areas in Idaho and Washington have met with controversy. The future of the grizzly bear will depend on human willingness to share their habitats with the bears and set aside areas of wilderness large enough for them to survive.