Before the US detonated two nuclear weapons over the Japanese cities of Hiroshima and Nagasaki on August 6 and 9, 1945, another less destructive but still explosive idea was proposed, attaching time-release incendiaries to Mexican free-tailed bats.
First conceived by a dental surgeon from Irwin, Pennsylvania named Lytle S. Adams who was an acquaintance of First Lady Eleanor Roosevelt. Adams convinced President Roosevelt that some kind of container holding them could be dropped over Japanese cities after dark and come dawn the bats would simply roost.
The plan isn’t as strange as it might first sound as Japanese cities were largely constructed of wood and paper at the time, so when the roosting bats exploded it would have caused thousands of fires and burned large sections of these cities to the ground.
Adams would assemble a somewhat eclectic team consisting of the mammalogist Jack von Bloeker, actor Tim Holt, a former gangster, and a former hotel manager, among others to determine and then test several variables to make the project feasible.
Each bomb would contain 26 trays that each held 40 hibernating bats. Each bat was meant to be outfitted with an individual incendiary device that was set to detonate after a specified amount of time. The bombs could deploy their own parachutes, giving the bats time to fly out and look for places to roost.
Not everything would go to plan however when in one incident, the Carlsbad Army Airfield Auxiliary Air Base near Carlsbad, New Mexico, was set on fire on May 15, 1943, when armed bats were accidentally released. The bats roosted under a fuel tank and incinerated the test range.
The project would never get past the test stage and would eventually be scrapped after the development of the A-Bomb.