“As recently as the Second World War, militaries weaponized animals.”

HUMANS HAVE BEEN domesticating animals for use in combat since the first warriors of Eurasia rode into battle on horses around 3000 BCE. But what about using animals themselves as weapons?

The defenders of the Greek city Magara did just that in 266 BCE. According to the ancient historian Poluainos, when Macedonian conqueror Antigonus II Gonatas besieged the city, the heavily outclassed and outnumbered defenders unleashed a devastating secret weapon on the invaders’ phalanxes and war elephants. They used flaming pigs.

The pigs, which were doused in flammable oil or pitch, were pushed out of the city gates and then somehow set ablaze. The burning animals scattered, many of which drove straight into the enemy lines setting fire to the camp and worse, panicking the war elephants. The lumbering beasts broke ranks and fled, stomping any of the Macedonian infantrymen that got in their way.

Centuries later, when besieging cities, Roman Legions would harass defenders by lobbing beehives over the enemy walls using catapults. Not exactly lethal weapons, but they must have certainly been unpleasant to anyone in the area where one of these hive bombs hit.

As recently as the Second World War, militaries weaponized animals too. Consider the Soviet’s use of anti-tank dogs.

Inspired by the experiments Ivan Pavlov, Red Army researchers discovered they could condition dogs to dart under tanks by placing containers of food beneath the vehicles in training areas. Later, the Russians planned to strap 20 lb. bombs to the dogs and turn them loose near German tanks. The dogs, which would have been starved for days, were expected to dart under enemy tanks in search of food. A protruding switch from the bomb pack would make contact with the underside of the tank and touch off the charge crippling the vehicle, but killing the animal in the process.

When tested in battle for the first time in 1941, 30 dogs were unleashed on a column of panzers. Only four detonated under or near enough to the tanks to inflict any damage. In fact, most of the dogs were frightened by the sound of the battle and fled. A half dozen of them actually sought cover in Soviet trenches where they exploded killing and injuring Red Army soldiers.

As the anti-tank dogs were deployed in subsequent battles, other deficiencies were discovered. The dogs were trained using Russian tanks, which ran on diesel; German tanks ran on gasoline. The dogs often went straight for any Russian tanks and exploded, most likely because of the more familiar smelling diesel exhaust.

The practice was also understandably unpopular with the Soviet troops. Many felt it was needlessly cruel. The criticism became so widespread that military authorities had to clamp down on dissenters.

German propagandists made much of the canine kamikazes, suggesting that it was a sign that the Soviets were truly on their last legs. Yet the Red Army heralded the practice as a rousing success that resulted in the destruction of 300 Nazi tanks, a claim that historians have disputed. The use of the dogs declined in 1942.

It wasn’t just the Soviets who experimented with using animals as delivery systems for bombs.

During the Second World War, the United States military spent $2 million on a top-secret experimental program involving exploding bats. The scheme involved fitting Mexican free-tailed bats being with 6 oz. incendiary bombs and then releasing them over Japan. Strategists predicted that the bats would disperse over the target area, eventually seeking shelter in the attics and under the eaves of the largely wood and paper buildings of Japanese industrial cities. The timed charges would then explode once the bats had roosted, creating hundreds of thousands of small fires would spread quickly consuming entire cities. The bats would be collected and packed into large canisters that would contain more than 1,000 of the winged rodents. A single B-24 could carry 100 of the canisters that would be dropped from 5,000 feet.  A parachute on each canister would slow the descent. The casing would then open and release the bats, which would then nest in buildings. The military believed a flight of 10 Liberators flying from Alaska could deliver more than 1 million bat bombs.

The weaponized bats were tested at Carlsbad, New Mexico in 1943, where they proved themselves all too effective. The bats caused fires well beyond the test range, with one nesting beneath a fuel tank on the base. Additional tests were conducted at El Centro, California and Dugway Proving Grounds in Utah.

Fortunately for the bats, by the time the weapon was ready for deployment in mid-1945 conventional firebombing was already effectively incinerating Japan. And with the two atom bombs nearly ready to be dropped, the military had no use for its bat bombs.

The plan remained a military secret until details of it leaked in the 1950s.