A man eats in front of his Basset Hounds during the first day of the Crufts Dog Show in Birmingham, Britain March 9, 2017. (Photo by Darren Staples/Reuters)

A stray puppy walks along abandoned train tracks near the Chernobyl nuclear power plant on August 19, 2017 near Chornobyl, Ukraine. An estimated 900 stray dogs live in the exclusion zone, many of them likely the descendants of dogs left behind following the mass evacuation of residents in the aftermath of the 1986 nuclear disaster at Chernobyl. (Photo by Sean Gallup/Getty Images)

Disabled dogs outfitted with wheelchairs walk at an animal rescue center on July 12, 2008 in Chengdu of Sichuan Province, China. The center has adopted over 100 stray dogs and cats from quake-struck areas. Those who were hurt or disabled are outfitted with a cart to help support they're body and make them mobile. (Photo by China Photos/Getty Images)

Throughout the course of the long war in Afghanistan, Coalition troops have relied on thousands of military working dogs to help keep them safe, and make their jobs easier. The dogs are trained to detect explosives, to find illegal drugs, to search for missing comrades, or target enemy combatants. Not only are they active on the front lines, but behind the lines they serve as therapy dogs, service dogs, and loyal companions. They also share the same risks as the ground troops, suffering injuries and sometimes death on the battlefields. Gathered here are images of these dogs and their handlers in Afghanistan and back home, from over the past several years, part of the ongoing series here on Afghanistan.

At first, British photographer Martin Usborne just wanted to do some reporting on people who leave their dogs locked up in cars. But as he went around scouring parking lots, “making barking noises to try and awaken sleeping dogs that were not actually there,” his project took on a new artistic direction. “The Silence of Dogs in Cars” was inspired by a “childhood memory of waiting in a car whilst his parents were shopping in a supermarket, and the youthful fear that they would not return.”