Ledger drawing of Northern Cheyenne war leader and warriors (left) coming to a truce with a Crow leader counterpart after a battle (artwork circa 1880 or about eight years after Yellowstone was created and four years after the Battle of the Little Bighorn). More than 27 tribes have a historical connection to the lands in and around present-day Yellowstone, including tribes that, at various points, were enemies. Dr. Doyle's research and that of colleagues reveals that indigenous habitation of the region extended, at least seasonally, to some of the highest reaches of the Beartooth Mountains northeast of the national park. It could unlock some insights into how people coped with earlier expressions of climate change. Artwork public domain.