A newborn baby pangolin climbs the walls of a cage in Bangkok, Thailand April 20, 2011. The Thai custom office showed 175 pangolins they found hidden in a truck heading into Bangkok. (Photo by Damir Sagolj/Reuters)

Young Buddhist novice monks play at a Tibetan nomadic summer grazing area on July 24, 2015 on the Tibetan Plateau in Yushu County, Qinghai, China. Tibetan nomads face many challenges to their traditional way of life including political pressures, forced resettlement by China's government, climate change and rapid modernization. The Tibetan Plateau, often called “The Roof of the World”, is the world's highest and largest plateau. (Photo by Kevin Frayer/Getty Images)

A racehorse is hoisted up before its operation at Veliefendi equine hospital in Istanbul March 3, 2015. A state-of-the-art hospital for hundreds of horses run by the Jockey Club of Turkey at Istanbul's Veliefendi racecourse is the country's oldest and biggest. Grooms and trainers at the equine clinic work with vets and nurses while owners hope their prize runners, often worth hundreds of thousands of dollars, will recover quickly and then run faster still. (Photo by Murad Sezer/Reuters)

A man is seen wrapped with pythons, some which include the Albino Burmese Python, as part of a show celebrating the coming Year of the Snake in the Chinese calendar, while spectators look on, in Malabon city, north of Manila, Philippines, December 28, 2012. (Photo by Romeo Ranoco/Reuters)

Tanzania, 1964. A touching moment between primatologist and National Geographic grantee Jane Goodall and young chimpanzee Flint at Tanzania's Gombe Stream Reserve. (Photo by Hugo van Lawick via National Geographic)

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.

Storm clouds blanket the sky over Great American Ball Park as Starlin Castro #13 of the Chicago Cubs fields a ground ball in the fifth inning against the Cincinnati Reds as on July 7, 2014 in Cincinnati, Ohio. (Photo by Jamie Sabau/Getty Images)

Vehicles clog a highway during a hazy day in Beijing, China, Wednesday, February 26, 2014. Beijing remained cloaked in hazardous white pollution hiding much of its skyline Wednesday, despite the announced closures or production cuts at 147 of the city's industrial plants. (Photo by Ng Han Guan/AP Photo)