A Montana-based wilderness guide has passed away two days after being mauled by a grizzly bear near Yellowstone National Park on Thursday. Carl Mock of West Yellowstone, Montana, was attacked by the bear while fishing along the Madison River. Officials say the bear may have been defending a nearby moose carcass. Mock suffered severe wounds to his face and scalp but was able to call 911 after the attack, and was transported by rescuers via toboggan and snowmobile to a nearby hospital. A day after the attack on Mock, officials say the same bear was shot and killed after charging another group. The guide died Saturday.