Both cats and dogs have served as mascots and pets during wartime, but while cats were useful for pest control, dogs had a rather different set of duties, including tracking, scouting, serving as sentries, and carrying messages into battle. Here are some of the animal soldiers who served as man's best friend in war.

Jumbo, General Joffe's Bulldog mascot, wounded by a piece of shrapnel during the battle of Arras, 1917

(Photo by W. G. Philips/Philips/Getty Images)

Italian soldiers with their dog team during WWI, 1917

(Photo by Topical Press Agency/Getty Images)

Victory the Bulldog posing on a tank in Trafalgar Square during a campaign to sell War Loan certificates, November 1917

(Photo by Topical Press Agency/Getty Images)

Reporters at the front line with Spanish Republican troops. Ernest Hemingway (in glasses) can be seen in the background, c. 1937

(Photo by London Express/Getty Images)

A Bulldog stands guard outside a block of flats in South London, September 1939

(Photo by Fox Photos/Getty Images)

A member of the British Expeditionary Force with his mascot smiles form the train window having been safely evacuated back home from France, May 1940

(Photo by Topical Press Agency/Getty Images)

Anti-aircraft gunners using binoculars to check for enemy aircraft watched by a dog, c. 1940

(Photo by London Express/Getty Images)

Hoy, the dog mascot of the minesweeper HMS Bangor, being held by a member of the crew, May 1941

(Photo by Arthur Tanner/Fox Photos/Getty Images)

Flight Lieutenant Eric Stanley Lock, carries a dog near his aircraft featuring 26 swastikas showing his 26 Nazi kills, July 1941

(Photo by J. A. Hampton/Topical Press Agency/Getty Images)

A despatch rider in a Quebec regiment gives a lift to the regimental mascot, a British bulldog, October 1941

(Photo by Payne/Fox Photos/Getty Images)

American troops and a pet dog, looking at a scrapbook, during training in Northern Ireland, March 1942

(Photo by Fox Photos/Hulton Archive/Getty Images)

Army aviation cadets meet Fala, President Franklin D. Roosevelt's dog, who accompanied his Chief on Tour of Inspection of Southeast War Establishments, Maxwell Field, Alabama, April 1943

(Photo by AP)

A well camouflaged Marine is giving silent instructions to a Marine Corps jungle-trained dog on the front lines of the beachhead in Bougainville, Solomon Islands, January 1944

(Photo by AP)

A U.S. Marine chats with his scouting dog in Guam in August 1944. These dogs were used to track down Japanese soldiers hidden in caves or jungle strongholds, and for running messages.

(Photo by AP)

A veterinarian bandages an injured paw of Thunders of the 38th dog platoon, 85th division, September 1946

(Photo by AP)

Lt. Joseph Leroy holds the mascot of the 35th fighter interceptor wing, in a F-15 Mustang in Korea, January 1951. The dog was found in Japan by some Air Force men, who named him Admiration.

(Photo by AP)

Two Air Force Men and Admiration, the mascot of their wing, on a wing of a fighter plane in January 1951

(Photo by Jim Pringle/AP)

U.S. paratrooper Sgt. James R. Cone, holds a puppy that nipped him as he groped about in a cave entrance on a river bank in Lam Dong Province, Vietnam, July 1966

(Photo by Henri Huet/AP)

American marines with their pet dog in Vietnam, 1968

(Photo by Express Newspapers/Getty Images)

A soldier of the US Seventh Marines carrying a little puppy in his pocket after rescuing it during an operation southwest of Da Nang in Vietnam, January 1968

(Photo by Keystone/Getty Images)

U.S. Army Sgt. John Cobb keeps his dog, J.C., warm inside his coat while waiting for the arrival of the U.S. command ship, the USS LaSalle, in Kuwait City, March 1991

(Photo by AP/Greg Gibson)

U.S. Army Staff Sgt. Kevin Reese and his dog Grek waiting at a safe house, April 2007

(Photo by Staff Sgt. Stacy L. Pearsall/U.S. Air Force)

A military working dog wears doggles to protect his eyes as a Chinook helicopter takes off in Afghanistan, May 2010

(Photo by Sgt. Jason Brace/U.S. Army)