According to the book Bat Bomb, the World War II Project X-Ray explored the use of bombs filled with bats:
The basic idea was that a bomb-like canister filled with bats would be dropped from high altitude over the target area. The bats would be in a sort of hibernation, but as the bomb fell (slowed by a parachute) they would warm up and awaken. At the appropriate altitude, the bomb would open and over one thousand bats, each carrying a tiny time-delay napalm incendiary device, would flutter away and roost in various nooks and crannies, many of them in extremely flammable wooden Japanese buildings. The napalm devices would go off more or less simultaneously, and thousands of little fires would start at the same time. Many of them would grow into large fires, and the ability of the Japanese firefighters to contain them would quickly be overwhelmed.
Weird and wild stuff…
