War elephants were a terror to behold. They were huge, imposing animals; more than capable of defending themselves on their own. More than once in history armies have lost their will to fight after seeing them in the enemy’s ranks.
However, one of the problems with war elephants was that, once startled, they were just as much a liability to their owners as a threat to the enemy. A panicked three-ton animal is going to do some damage and it is not going to care what that damage hits. You could simply hope that the heat of battle would prove too much, but easier methods did exist. The trick was to find out what the elephants feared.
The Roman author Pliny named two things. The first was mice. His translated works read, “of all other living creatures, they cannot abide a mouse or rat.” This is probably the origin of the elephants versus mice myth so commonly found in popular culture. No records exist of Romans using mice in war. However, the second recommendation met with more success. Pigs, especially their cries, could be used to scare the elephants.
It was a trick well-known in India and likely brought to Western Europe by Alexander the Great. The Greeks and Romans made great use of this tactic. Historians record the defeat of both Pyrrhus (275 BC) and Antigonus (266 BC) due to the pigs’ squeals. The pigs could be made to squeal in a number of ways, although the most alarming must have certainly been by setting them on fire. The pigs, herded onto the battlefield and slathered in pitch, were set alight and let wild.
I don’t feel like it is a great jump to say that this must have also been extremely startling for the human soldiers as well.