We trek through knee-deep snow along the banks of the Gros Ventre River near Jackson until we come to a heap of bones and grass. It's what remains of an elk calf.
“Here you go,” he says. “This is what it looks like. And I can tell you on Friday, we were standing in a foot of snow. I tracked the whole attack.”
Mark Elbroch is a Wildlife Researcher with Panthera's Puma Project. He tells the story with pride. He’s known this mountain lion, F61, since she was a kitten.