Military animals have been used in various wars and conquests throughout time. Alexander the Great made use of elephants. War pigeons were popular in WWII to ferry messages across enemy lines. And, of course, horses have been used in both ancient and modern warfare.
Dogs have also seen their share of war combat over time. Ancient Greek writings tell of their presence in various conflicts. Many countries still use canines today in both combat and peacetime missions.
Read about a few modern military dogs and their handlers in these gripping accounts:
Always Faithful: A Memoir of the Marine Dogs of WWII by William Putney
Soldier Dogs: The Untold Story of America's Canine Heroes  by Maria Goodavage
The Dogs of War: The Courage, Love, and Loyalty of Military Working Dogs  by Lisa Rogak
Sergeant Rex: The Unbreakable Bond Between a Marine and His Military Working Dog  by Mike Dowling