Canyon rattlesnake, mile 173. This rattlesnake is red, adapted to the red rocks of the canyon. USGS geologist Ed McKee first noted them in the 1930s when he was studying the Hermit and Supai formations for the USGS, the main red beds of the Paleozoic. He told me that no one believed that the snakes had adapted to the rock coloration. So, one morning when he was working, he captured one. Having no bag to put it in, he drove the nearly 100 miles to Flagstaff to show the snake, holding it behind the head, out the window of his car.