Gardener Peter Glazebrook poses for photographers with his world record breaking onion at The Harrogate Autumn Flower Show on September 16, 2011 in Harrogate, England. Peter Glazebrook from Newark, Nottinghamshire claimed a Guinness World Record with his giant onion weighing 8.150 kg. (Photo by Christopher Furlong/Getty Images)

A caterpillar driven ferry with a 24 horsepower engine takes holidaymakers from the mainland at Bigbury in Devon to Burgh Island, a quarter of a mile away. (Photo by Reg Speller/Fox Photos/Getty Images). 4th April 1935

Soldiers, including two recruits who have brought some chickens, at Victoria prepare to board the train for the battle front. (Photo by Hulton Archive/Getty Images)

Two women pose as they drink real ale at the Great British Beer Festival in the Olympia exhibition centre on August 13, 2013 in London, England. The festival, which runs until August 17, 2013, has over 24 bars serving over 800 different beers, ciders and perries. (Photo by Oli Scarff)

Fighters Holly “The Lotus” Mei (L) and Teri “Feisty Fists” London train for the upcoming 'Lingerie Fighting Championships 22: Costume Brawl I' at DXG Self Defense on October 25, 2016 in Las Vegas, Nevada. The event is scheduled to feature eight bouts at 4 Bears Casino & Lodge on October 29, 2016 in New Town, North Dakota. (Photo by Ethan Miller/Getty Images)

The new curvy Barbie doll body shape (L) is seen next to the traditional Barbie in a combination of photos released by Mattel on January 28, 2016. Barbie, the world's most famous doll, has a new body. In fact, she has three new bodies – petite, tall and curvy. Some 57 years after the impossibly busty and narrow-waisted blue-eyed Barbie doll was first introduced, California-based toy maker Mattel on Thursday released the new models, which it says better reflect a changing world. (Photo by Reuters/Mattel)

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.

Female Chimpanzee “Fifi” eats carrots as she sits in her enclosure at Taronga Zoo on her 60th birthday May 21, 2007 in Sydney, Australia. Fifi is the oldest of the Zoo's chimp population, which consists of 19 individuals. (Photo by Ian Waldie/Getty Images)