The two adults and one adolescent grizzly were probably killed at different times during the previous two weeks when they touched the live powerlines. A fallen tree had stretched the line close to the ground, but since it never broke, Montana Power remained unaware of the accident.
Environmental groups in the region say the deaths prove that a recent proposal to remove Yellowstone grizzlies from the federal endangered species list is premature. "This just puts more pressure on them to slow down the delisting process," Matt Reid of the Great Bear Foundation told the Salt Lake Tribune. "If bears aren't safe in Hayden Valley, that's bad."
Biologists think the bears were using the power corridor as a travel route and may have been attracted by the buzzing of the charged line.