War has long made heroes of women and men. But animals have also shown gallantry in battle stretching back centuries, including dogs, bears, cats, a duck and even a goat called Sergeant Bill.

In World War I, Sergeant Bill, who hailed from Saskatchewan and was called Billy by his comrades, was credited with helping to save three Canadian soldiers by butting them into a mud-filled trench just seconds before a shell exploded.

During his military career, Bill was also arrested after chewing army property and suffered from trench foot. After the war he returned home to Canada and, following his death, was stuffed and put on display at the Broadview Historical Museum in Saskatchewan.

Decades later, an American carrier pigeon called G.I. Joe saved as many as a thousand lives during World War II by flying 20 miles in 20 minutes with a message warning Allied forces not to bomb an Italian village that had been retaken by the British.