| Bat bomb | |
|---|---|
 Bat bomb canister later used to hold the hibernating bats. | |
| Type | Bomb |
| Place of origin | US |
| Service history | |
| In service | Never used |
| Wars | World War II |
| Production history | |
| Designer | Louis Fieser |
| Designed | January 1942 |
| Specifications | |
| Mass | 123 kg (271 lb) |
| Length | 123 cm (48 in) |
Bat bombs were an experimental World War II weapon developed by the United States. The bomb consisted of a bomb-shaped casing with over a thousand compartments, each containing a hibernating Mexican free-tailed bat with a small, timed incendiary bomb attached. Dropped from a bomber at dawn, the casings would deploy a parachute in mid-flight and open to release the bats, which would then disperse and roost in eaves and attics in a 20–40-mile radius (32–64 km). The incendiaries, which were set on timers, would then ignite and start fires in inaccessible places in the largely wood and paper constructions of the Japanese cities that were the weapon's intended target. The United States Navy took control in August 1943, using the code name Project X-Ray.