A walruses at Hagenbeck Zoo in Hamburg, Germany on July, 7, 2015. (Photo by Werner Struss/Startraks action)

Girls Aloud: Nicola Roberts, Kimberley Walsh, Sarah Harding and Cheryl Cole at Kimberley Walsh's birthday party hosted by Damian Darkko at Mint Nightclub in London, Britain on November 25, 2006. The Girls Aloud star Sarah Harding has died at the age of 39, her mother has said in a post on Instagram. Issue date: Sunday September 5, 2021. (Photo by Rex Features/Shutterstock)

Italian actress Zaina Dridi walks the red carpet for “Carol” during the 10th Rome Film Fest at Auditorium Parco Della Musica on October 22, 2015 in Rome, Italy. (Photo by PA Press Association Images)

Peruvian surfer Domingo Pianezzi rides a wave with his alpaca Pisco at San Bartolo beach in Lima March 16, 2010. Pianezzi has spent a decade training dogs to ride the nose of his board when he catches waves, and now he is the first to do so with an alpaca. (Photo by Pilar Olivares/Reuters)

A general view of atmosphere at the annual VOLT Festival in Sopron, 208 kms west of Budapest, Hungary on August 16, 2016. (Photo by Rockstar Photographers)

A bus goes through a flooded street in Wuhan, Hubei province, China July 6, 2016. (Photo by Reuters/China Daily)

People walk during a polluted day in Shenyang, Liaoning province, March 31, 2016. (Photo by Reuters/Stringer)

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.