As seen through a night-vision device, Marine Corps Cpls. David Hernandez, left, and Harold Greenaker, and Ella and Kuko, their military working dogs, provide security outside a house while their team members prepare for extraction during an urban training exercise on Guam, Jan. 13, 2016. Hernandez and Greenaker are dog handlers. Ella is a specialized search dog and Kuko is a specialized explosive detection dog. The Marines and dogs are assigned to Maritime Raid Force, 31st Marine Expeditionary Unit. U.S. Marine Corps Photo by Cpl. Thor J. Larson