The earliest examples of using animals as weapons usually involves setting them on fire and pointing them at your enemy’s villages or camps. The obvious flaw in this method is that there is just as much chance that the burning animal may turn around and cause destruction to your camp as it may your opponent’s. Rats were used mostly in this capacity as living ambient torches until they became used in one of the earliest examples of biological warfare. In 1346, during the seige of the Genoese city of Kaffa by Tartar forces under Janibeg, plague was spreading among the Tartars outside the city weakening their chance at keeping the seige going. In a last ditch attempt, the Mongol army started catapulting dead rats and corpses of plague victims into the city in hopes to spread the disease. A few Genoese ships tried to escape from the spreading plague and made their way back to Italy where the Black Death than spread throughout Europe.
The latest use of rats in the military are in detecting landmines.. A Belgian company has trained African pouch rats, also called Gambian Pouch Rats, to locate buried bombs and landmines. The rats are trained to smell explosive material by associating it with a food reward. They have several advantages over the use of using dogs in locating landmines since they are cheaper to train and their small size will rarely trigger a mine as they find them. They are currently being used in Mozambique to clear the landmines from its civil war.