The strongest war dogs, broad-mouthed breeds of mastiff specifically trained for battle , were used against almost nude troops. The Spanish conquistadors used armoured dogs that had been trained to kill and disembowel when they invaded the land controlled by South American natives. They were used to flush out ambushes by sending the dogs out ahead of columns.
The use of dogs in warfare has been common even in many early civilizations. As warfare has progressed, their purposes have changed greatly. Some examples are:
- 628 BC: The Lydians deployed a separate battalion of fighting dogs.
- 525 BC: Cambyses II used huge fighting dogs against Egyptian spearmen and archers.
- 490 BC: Battle of Marathon: A brave fighting dog was immortalized in a mural.
- 385 BC: Siege of Mantineia: Fighting dogs cut off enemy reinforcements.
- 101 BC: Battle of Vercellae: Large Cimbri dogs led by women defended their wagon forts.
- 1525: Henry VIII exported 400 mastiffs to support Spain.
- 1580: Elizabeth I sent 800 fighting dogs to fight in the Desmond Rebellions.
- 1799: Napoleon assembled large numbers of fighting dogs in front of his reserves.
- 1914: The Belgian Army used carabiniers, strong-muscled Bouvier des Flandres to haul heavy machine guns to the front.
- 1914–1918: Dogs were used by international forces to deliver vital messages.
- 1941–1945: The Soviet Union used dogs strapped with explosives to destroy invading German tanks.
- 1943–1945: The United States Marine Corps used dogs, donated by their American owners, in the Pacific theater to help take islands back from Japanese occupying forces. During this period the Doberman Pinscher became the official dog of the U.S.M.C.; however, all breeds of dogs were eligible to train to be "war dogs of the Pacific". Of the 549 dogs that returned from the war, only 4 could not be detrained and returned to civilian life. Many of the dogs went home with their handlers from the war.
- 1966–1973: Approximately 5,000 US war dogs served in the Vietnam War (the US Army did not retain records prior to 1968); about 10,000 US servicemen served as dog-handlers during the war, and the K9 units are estimated to have saved over 10,000 human lives. 43 military working dogs and 73 US servicemen working as dog handlers were killed in action during the war. Only 200 Vietnam War dogs returned to the U.S. with their handlers; the rest were euthanized or left behind.
- 1979–1988: The Soviet Union again used dogs, this time in the Soviet war in Afghanistan.
- 2011: United States Navy SEALs used a Belgian Malinois war dog named Cairo in Operation Neptune Spear, in which Osama bin Ladenwas killed.