A Yellowstone bull bison with a gigantic abscess on its right rear quarter probably isn’t suffering much pain and will likely survive, one of the county’s top bison ranchers says. After seeing a photo of the bison, taken early Wednesday in Yellowstone National Park’s Lamar Valley, Klemm said a gushing rupture of the abscess is imminent. The abscess probably formed around a wound, he said. The bison rut, or mating season, is on in Yellowstone. The bull might have suffered a puncture during a fight with another bull, Klemm said.