I was camping in Yosemite Valley next to some friends who had a pop-up. After dark we were sitting in my trailer and heard a metallic banging sound. The bears occasionally make the rounds through the campgrounds banging into the bear boxes to see if someone hasn't fully latched them and they will pop open. We watched a good-sized bear shoulder into the bear box in my friends site. It sprang open. In a split second the bear pulled out the ice chest, opened it and stuck his head in. We jumped up, grabbed some pots and ran outside banging on the pots. The bear's head jerked up out of the ice chest with a package of bratwurst in his mouth. He stared at us a moment then ran off carrying the bratwurst.
