Joshua Patino stands on a ladder to put finishing touches on a giant dinosaur exhibit at PAX East in the Boston Convention and Expo Center, Thursday, April 21, 2016, in Boston. PAX East, an annual celebration of gaming culture, is expected to draw tens of thousands of visitors Friday through Sunday. It's a place where serious gamers can preview unreleased video games and devices, compete in tournaments, hear live music and meet others for whom gaming is a way of life. (Photo by Elise Amendola/AP Photo)

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.

A Vietnamese woman, wearing the traditional “ao dai” long dress, poses for photos along peach blossom flowers ahead of the Vietnamese “Tet” (Lunar New Year festival), in a field in Hanoi, Vietnam, February 2, 2016. (Photo by Reuters/Kham)

A Lion-Tailed macaque holds a big block of ice with a mix of frozen vegetables and fruit at the zoo in Leipzig, central Germany, Friday, July 19, 2013. Weather forecasts predict sunny weather and warm temperatures for Germany in the next few days. (Photo by Jens Meyer/AP Photo)

A customer asks for the price of a bittergourd at Duri market on a railway track in Jakarta, January 8, 2016. Indonesia's annual inflation rate cooled to the lowest in six years in December, which might pave the way for the central bank to cut a benchmark rate held at 7.50 percent since February 2015. (Photo by Reuters/Beawiharta)

A girl collects drinking water at Dala river outside Yangon, Myanmar March 3, 2016. Some 650 million people, or one in 10 of the world's population, have no access to safe water, putting them at risk of infectious diseases and premature death. Dirty water and poor sanitation can cause severe diarrhoeal diseases in children, killing 900 under-five a day across the world, according to United Nations estimates. (Photo by Soe Zeya Tun/Reuters)

A Filipino girl is carried along a flooded road in suburban Mandaluyong, east of Manila, Philippines, as monsoon downpours intensify while Typhoon Nepartak exits the country on Friday, July 8, 2016. In the Philippine capital, Manila, and outlying provinces, classes in many schools were suspended and at least six flights, including one scheduled to come from Taiwan, were canceled because of stormy weather and floods following monsoon downpours intensified by the typhoon, Filipino officials said. (Photo by Aaron Favila/AP Photo)

A long exposure image of embers flying off burnt out trees following the wind driven wildfire ranging in the mountain area near Rancho Cucamonga late 30 April 2014. Earlier in the day more than 1,500 homes were evacuated as the Etiwanda fire charred around 1,000 acres in San Barnardino National Forest. (Photo by Stuart Palley/EPA)