The dogs of war
These four-legged heroes are often a soldier's best friend

A Red Cross dog finds a wounded soldier, circa 1917.
(Hulton Archive/Getty Images)The United States first introduced its canine corps during World War II. In an attempt to fill out its four-legged ranks on short notice, the military put out a c

A French officer writes a message while a dog stands by ready to deliver it, circa 1939.
(Topical Press Agency/Getty Images)

Three Airedale dogs wear special gas masks at a kennel in England, circa 1939.
(Keystone/Getty Images)

An Alsatian defense dog lays a telephone cable in an unknown location on Nov. 12, 1940. The dog would carry a mile of cable, being let out from a roll on her back, over bomb-pitted, barbed-wire-entangled ground, in just two minutes.
(AP Photo)

A German Shepherd who works as an ammunition carrier, alongside a soldier in a gun pit in the Eastern Command area of Great Britain on Sept. 3, 1941.
(AP Photo/British Official Photo)

A camouflaged Marine gives silent instructions to a jungle-trained dog on the front lines of the beachhead in Bougainville, Solomon Islands, on Jan. 13, 1944, during World War II.
(AP Photo)

A scout dog, fighting against a strong current, swims across a muddy stream during an operation west of Saigon on Sept. 13, 1968. The dog's handler uses cable to work his way across.
(AP Photo)

A Labrador retriever scout dog aids U.S. soldiers near Phong Phu in Vietnam on Nov. 10, 1967.
(AP Photo)

A sergeant and his dog run for cover during a gun battle with suspected Taliban militants near the village of Jilga, Afghanistan, on July 8, 2010.
(REUTERS/Bob Strong)

A Marine sits with his improvised explosive device–sniffing dog, Bee, as he tries to cope with the death of a fellow soldier during a patrol on October 17, 2010, in Kajaki, Afghanistan.
(Scott Olson/Getty Images)

A soldier pets an explosives-sniffing dog in Kandahar, Afghanistan, on June 26, 2011.
(REUTERS/Baz Ratner)