Grizzly bears in Greater Yellowstone have elevated levels of lead in their blood, a new study shows.
Unlike previous studies in ravens and eagles, researchers could not link the high lead levels to bullet fragments in gut piles left behind by hunters.
Researchers from Craighead Beringia South and the University of Montana studied lead levels in 82 grizzly bear blood samples, 35 black bear samples, six mountain lion samples and 12 wolf samples. The blood was provided by the Wyoming Game and Fish Department, the Interagency Grizzly Bear Study Team, Grand Teton National Park and the U.S. Fish and Wildlife Service. Craighead Beringia South also contributed blood samples.
More than one sample might have come from the same animal, but the blood was collected at different times.
Researchers also looked for lead bullet fragments in coyote and bear scat. They fund none.
Grizzly bears showed the highest blood-lead levels, followed by black bears. Wolves and mountain lions showed very little blood contamination.
The findings appear in the latest issue of the Journal of Wildlife Management.