The Boars of War

War pigs, also known as incendiary pigs, are those pigs speculated to have been used at most rarely in ancient warfare as a countermeasure to war elephants. The pigs were allegedly covered with tar, pitch, olive oil, or other flammable materials, set on fire, and driven towards enemy war elephants, with the intention that the elephants, terrified by the piercing squeals and oncoming flames, would flee in panic through the lines of their drivers' own army. Obviously, a burning pig is difficult to command and thus easily could quickly turn into a loose cannon and cause harm to friendly soldiers. However, the hope of stopping war elephants was enough to make war pigs a desirable tactic.

Pliny the Elder reported that "elephants are scared by the smallest squeal of a pig" (book VIII ch. 9). Antipater's siege of Megara during the Wars of the Diadochi was reportedly broken when the Megarians poured oil on a herd of pigs, set them alight, and drove them towards the enemy's massed war elephants. The elephants bolted in terror from the flaming squealing pigs often killing great numbers of the army the elephant was part of (Aelian, de Natura Animalium book XVI, ch. 36). The Romans would later use the squeals of pigs to frighten Pyrrhus' elephants, thus winning a great victory (ibid., book I ch. 38). Procopius, in book VIII of his History of the Wars, records the defenders of Edessa using a pig suspended from the walls to frighten away Khosrau's siege elephants.