Larry Stevens is an evolutionary ecologist and the Curator of Ecology at the Museum of Northern Arizona in Flagstaff, where he also serves as Director of MNA’s Springs Stewardship Institute. Over the past half century he has studied the ecology of the world’s most famous large deep canyon, and the river that carved it, working as a river guide and for the National Park Service, the Department of the Interior, several colleges and universities, and Grand Canyon Wildlands Council. With a PhD in Zoology from Northern Arizona University in 1989, he has written many scientific and popular works about Grand Canyon.