This adorable gallery reveals the astonished expressions of dozens of puppies as they try to gobble up treats flying through the air toward them. Photographer Christian Vieler, 48, has been documenting pooches, with their eyes bulging, mouths wide open and looks of love on their faces, in his studio as part of the project “Dogs Catching Treats” since 2013. (Photo by Christian Vieler/Caters News Agency)

Dogs and their owners dressed in Halloween costumes parade during the annual Haute Dog Howl'oween event in Long Beach, California on October 30, 2016. The parade, which claims to be the largest Halloween dog event in the world, sees hundreds of dogs and their owners dressed in colorful costumes celebrating the festival. (Photo by Mark Ralston/AFP Photo)

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.

A dog sanctuary in Mexico is the first of its kind as it provides troubled canines with a safe and loving home. Milagros Caninos (Miracle Dogs) is a sanctuary in Mexico City that takes in abused, elderly, terminally ill, and disabled dogs.

Cat-Friend vs Dog-Friend, Two Humans Acting Like House Pets

Mushers and their huskies practice at a forest course ahead of the Aviemore Sled Dog Rally on January 24, 2016 in Feshiebridge, Scotland. Huskies and sledders prepare ahead of the Siberian Husky Club of Great Britain 34th race taking place at Loch Morlich this weekend near Aviemore. (Photo by Jeff J. Mitchell/Getty Images)