Incendiary pigs: Did Ancient Rome really set animals alight and use them in battle?

Ancient Rome maintained a military tradition that combined strict discipline with strategic adaptability that prioritised constant aggression.

These qualities enabled its armies to conquer and control an empire that stretched across Europe, North Africa, and the Near East.

Roman commanders often demonstrated an openness to unusual methods, which likely was a response to immediate tactical needs, especially when they faced unfamiliar threats or when they defended vulnerable positions against well-equipped enemies. 

Roman soldiers knew that sychological warfare, which often influenced battlefield outcomes, played an important role in their success.

To this end, public torture, executions, and displays of captured enemies were used to lower morale.

Engineers also constructed siege towers, rams, and torsion-powered artillery, but in moments of desperation, defenders sometimes resorted to makeshift tactics designed to disrupt enemy order.

Roman confrontations with war elephants often demanded creative solutions that tested commanders' skills.

These animals were introduced to the Mediterranean battlefield by Pyrrhus of Epirus during the early third century BCE and could smash infantry lines, destroy gates, and trample cavalry, which made them particularly dangerous when deployed in tight spaces during urban warfare. 

Because elephants responded poorly to fire and unpredictable noise, Roman generals often developed countermeasures, which included javelin-armed skirmishers, camouflaged ditches, and burning projectiles.

At the Battle of Zama in 202 BCE, Scipio Africanus reportedly arranged lanes through which the elephants could be channelled, and he reportedly used light infantry to harass them.

Later accounts suggested that Roman troops also used loud trumpets to confuse the elephants, although this detail does not appear in contemporary sources such as Polybius.

Some writers claimed that these strategies reportedly succeeded in turning the elephants back toward their own lines.

Over time, the use of fire as a weapon became closely associated with anti-elephant tactics.

For that reason, stories about fire-based animal weapons eventually became common in both military writings and popular retellings. 

The theory behind incendiary pigs was simple. Elephants feared fire. They also reacted unpredictably to high-pitched noise.

When both elements were combined, the effect could be disastrous for those standing nearby. 

According to some writers, defenders of besieged cities drove burning pigs into elephant formations.

The animals had been soaked in pitch or resin and set alight before release. As the pigs, which squealed, ran wildly through enemy lines, the elephants panicked and trampled their own troops.

Pigs were often easy to obtain and required no special training. Any livestock pen inside a besieged city could become a resource.

Since pigs already behaved wildly when frightened, commanders may have reasoned that adding fire would enhance the chaos.

For those facing overwhelming odds, this tactic may have felt like a small gamble with potentially large consequences. 

Some observers may have viewed the practice as consistent with other fire-based innovations already used in sieges.

Flaming arrows, which typically involved wrapping oil-soaked rags around the tips of shafts, could be launched, and fire pots filled with resin or bitumen could be hurled from walls.

Oil that had been set alight, often poured from cauldrons, caused severe injuries to attackers.

The idea of adding pigs to this list of incendiary weapons may have grown out of the same logic.

If a flaming projectile could sow panic, then a flaming animal might do so even more effectively. 

The most detailed account of incendiary pigs came from the siege of Megara, where the Macedonian king Antigonus II Gonatas used war elephants to assault the city in the early third century BCE.

According to the story, defenders may have released pigs that were covered in flammable substances.

Once set alight, the animals had charged the elephants, whose terror had caused them to retreat and trample their own soldiers.

The story appeared in Strategemata, written by Polyaenus of Bithynia, a Macedonian rhetorician who had compiled his work around 162 CE, and who may have relied on hearsay.

He included it as an example of clever military improvisation. 

However, the account had appeared several centuries after the event. Polyaenus had not cited eyewitnesses, nor had he offered any evidence for the story.

He aimed to entertain and instruct, not to provide reliable historical narratives. No earlier Greek or Roman sources had mentioned the event, and no surviving Roman military manuals, such as Vegetius' De Re Militari, had included it among recommended strategies. 

No archaeological evidence had so far supported the account. Burnt animal fragments, which had been found in military contexts, usually related to food preparation, ritual offerings, or accidental fire.

Nothing links them to deliberate use as incendiary weapons. At Roman siege sites such as Dura-Europos and Masada, fragments of oil amphorae, sling stones, and fire-damaged masonry had been common.

Yet no bones or traces had ever been identified as evidence that pigs set alight had been used in battle. 

Modern historians generally remain cautious when evaluating stories of incendiary pigs.

They recognise that writers such as Polyaenus did not follow modern standards of verification.

His work, valuable for understanding how ancient people saw warfare, cannot be a reliable source for what actually occurred.

Many of his accounts had followed a pattern: a weaker force had used deception to defeat a stronger one, often by shocking or humiliating means. 

Writers such as Livy, Frontinus, and Vegetius, who described military methods in great detail, had omitted any mention of such a tactic.

Since these authors covered both common and unusual battlefield tricks, their silence is significant. 

Several practical problems had also cast doubt on the story, making the tactic seem unlikely.

Pigs that had been set alight were impossible to control. Once released, they could run in any direction, including back toward friendly forces or into storage areas filled with hay or timber.

The risk of accidental destruction was enormous. Ancient cities were highly flammable and defenders would not have risked their own safety without clear evidence that the tactic would work. 

Additionally, elephants were typically rare and expensive and few battles featured them, while fewer still occurred in situations where pigs might be available in sufficient numbers.

As a result, the opportunity to deploy such a tactic would have been limited. It may have happened once, in one city, during one siege.

If so, the story had grown far larger than the event that inspired it. 

Ancient warfare often produced tales of animal-based weapons designed to spread confusion or fear.

Hannibal reportedly filled clay jars with venomous snakes and hurled them onto enemy ships during naval engagements.

According to Roman accounts such as those preserved by Frontinus, the snakes, once released, caused panic among sailors, who feared what they could not see or control.

This tactic was attributed to his time assisting King Prusias I of Bithynia during conflicts in Asia Minor and came well after the Second Punic War. 

Similarly, Chinese records from the Song dynasty mentioned monkeys with firecrackers tied to their tails.

Described in military texts such as the Wujing Zongyao compiled in 1044 CE, the monkeys were released into enemy camps during sieges.

The noise, movement, and fire startled troops and caused brief disorder. Indian sources also described war elephants that carried charges set alight.

The flames, which were intended to frighten both horses and foot soldiers, could also backfire and injure the elephants themselves. 

Each of these examples suggests a shared assumption that fear could often break discipline faster than weapons.

Commanders who lacked manpower or equipment often relied on showy tricks to disorient the enemy.

Whether the tactic caused serious harm was less important than whether it disrupted formations or broke morale. 

Such stories, which may contain fragments of truth, often attracted attention because of their striking detail.

They show how ancient cultures imagined warfare as a test of cunning as much as strength.

Even if flaming pigs never turned the tide of a battle, the idea survived because it captured a certain logic of survival: when all else failed, even the most alarming idea might be worth trying.