Wolf hunting and trapping that have killed more than 500 of the predators across the Northern Rockies. Hundreds of the animals have been killed -- mostly through hunting -- less than a year after being removed from the U.S. endangered species list. Restrictions on gray wolf harvests around Yellowstone are under consideration as the state prepares to kick off its inaugural wolf trapping season on Dec. 15, 2012. Conservation groups want limits on trapping after several wolves collared by park scientists for research were shot by Montana hunters in recent weeks.