Dogs in warfare have a very long history starting in ancient times. From being trained in combat, to their use as the scouts, sentries, messengers, mercy dogs, and trackers, their uses have been varied and some continue to exist in modern military usage.

Sergeant Stubby was a dog and the unofficial mascot of the 102nd Infantry Regiment and was assigned to the 26th (Yankee) Division in World War I. He served for 18 months and participated in 17 battles and four offensives on the Western Front. He saved his regiment from surprise mustard gas attacks, found and comforted the wounded, and allegedly once caught a German soldier by the seat of his pants, holding him there until American soldiers found him. His actions were well-documented in contemporary American newspapers.