Since ancient times, wild boars have been considered military animals. According to a legend, Alexander the Great used them as a secret weapon against the army of the Indian king Porus, who used war elephants. To make an elephant run away and destroy its own army, all that needs to be done is to make the pig squeal. This same trick helped defeat the army of Antigonus II Gonatas, but then he started to keep pigs close to the elephants to accustom these large animals to the squealing sound.