Mule School Marine Corps Sgt. Ryan D. Greenwalt demonstrates how to secure a mule during an animal packing course at Marine Corps Mountain Warfare Training Center in Bridgeport, Calif., Oct. 12, 2020. The course teaches students to use mules to travel through difficult terrain with mission-essential gear. SHARE: Download: Full Size (1.09 MB) Tags: Marine Corps Credit: Marine Corps Lance Cpl. Colton Brownlee VIRIN: 201012-M-ET234-1125M.JPG Photo Gallery