Episode 13 - Bat Bombs

Updated: Feb 6, 2020


Dr. Lytle Schooler Adams was a practicing dentist and oral surgeon from Pennsylvania and dabbled with inventions in his spare time. In 1927, Dr. Adams experimented with an airmail pick up-system that would allow for a plane to pick up mail in rural areas without ever having to land. The mail container would be suspended from ropes or cables suspended from two poles. The plane would swoop down with a hook hanging below and snag the cables with it. In 1934, Dr. Adams showed off his invention by making regular deliveries and pickups from the middle of the lagoon at the Chicago World’s Fair in 1934. The first lady, Eleanor Roosevelt, took an interest in Dr. Adam’s invention and he would sometimes take her in his own plane to different presentations of the invention.

In 1941, Dr. Adams went on a vacation to American Southwest. While in New Mexico, he visited the Carlsbad Caverns National Park, which is home to more than 100 caves and about a million bats. Adams was fascinated by the bats while he was there and continued to think about them even when he returned home to Pennsylvania.

On December 7, 1941 at 7:55 a.m. Hawaii time, 360 Japanese warplanes descended upon the United States naval base Pearl Harbor. President Franklin D. Roosevelt knew that a Japanese attack was possible, but America was still caught off guard when the air assault on the base began. Five of eight battleships, three destroyers, and seven other ships were sunk or extremely damaged and over 200 aircraft at the base were completely destroyed. 2,400 Americans were killed and another 1,200 were seriously wounded. Dr. Adams turned on his radio that day and listened to the horrors that were happening to Americans at the hands of the Japanese. He quickly began to devise a plan to seek revenge against Japan.

Adams started researching bats more extensively and even went back to Carlsbad to capture some bats. Adams learned that the most common bat in North America is the free-tailed bat the can eat more than twelve times it’s own size in insects in a single night and carry an external load almost three times it’s own weight. Using his connection to the first lady, Dr. Adams was able to get a letter to FDR that next month. The letter read:

“My Dear Mr. President:

I attach hereto a proposal designed to frighten, demoralize, and excite the prejudices of the people of the Japanese Empire.

As fantastic as you may regard the idea, I am convinced it will work and I earnestly request that it receive the utmost careful consideration, lest our busy leaders overlook a practical, inexpensive, and effective plan to the disadvantage of our armed forces and to the sorrow of the mothers of America. It is one that might easily be used against us if the secret is not carefully guarded.

I urge you to appoint a committee to study thoroughly and promptly all the possibilities of this plan and that its members shall consist of civilian eminently qualified to not only pass upon, but solve all technical matters and recommend methods for the execution of the raids.”

After listing several well-known scholars and businessmen that he would to head the study that he was proposing, he went on to write about his plan.

“Proposal for surprise attack : Remember Pearl Harbor

Shall the sun set quickly over “the land of the rising sun” I would return the call of the Japanese at Pearl Harbor on December 7, 1941, with a dawn visit at a convenient time in an appropriate way…

The lowest form of animal life is the Bat, associated in history with the underworld and regions of darkness and evil. Until now reasons for its creation have remained unexplained.

As I vision it the millions of bats that have for ages inhabited our belfries, tunnels, and caverns were placed there by God to await this hour to play their part in the scheme of free human existence, and to frustrate any attempt of those who dare desecrate our way of life.

This lowly creature, the bat, is capable of carrying in flight a sufficient quantity of incendiary material to ignite a fire.”

Adam’s letter goes on to explain how a million bats carrying small firebombs could be released an hour before dawn over an industrial city in Japan and they would do what bats do and go find dark, secluded places in the city to hide like factories, attics, lumber piles, power plants, etc. The bombs would then ignite all at once, exploding homes and factories so that the Japanese would be homeless and without places to work, but probably able to escape with their lives.

Since bats hibernate during winter, Adam’s explains that it would be easy to collect the bats and equip them with tiny bombs, then transport them, all without having to worry about feeding them or caring for them other than to maintain the conditions necessary for hibernation. They would then warm the bats up in order to wake them up when it was go time.

Adam’s letter ends with:

“An important consideration is that a bat weighs less than one-half ounce, or about 35 to the pound, which means that approximately 200,000 bats could be transported in one four-motored stratoliner type airplane, and still allow one-half the payload capacity to permit free air circulation and increased fasoline load. Ten such planes would carry 2 million fire starters.

In submitting this proposal it is with a fervent prayer that the plan will effectively be used to the everlasting benefit of mankind.

Yours humbly,

Lytle S. Adams”

Apparently, FDR didn’t think that this plan was insane and the proposal was sent to the National Research Defense Committee, which was in charge of looking into war-applicable ideas. Apparently back then, citizens were sending in all kinds of novel warfare ideas, and then committee would sift through them to see if there was anything worthwhile. The proposal was sent to the Army Chemical Warfare Service. It seems that because FDR seemed on board with the idea, everyone else just went with it. To be fair though, the government was already looking into pigeon-controlled missiles.

After receiving the go-ahead, Adams started to assemble his team of researchers. He hired Dr. Jack Von Bloeker, a mammologist from the LA County Museum, a pilot turned actor Lieutenant Tim Holt, brothers

Bobby and Eddie Herrold, ex-gangster Patricio “Patsy” Batista who claimed to have worked for Al Capone, another set of brothers Frank and Mark Benish, Ray Williams who was a lobster fisherman turned Marine, and Von Bloeker’s two high school student assistants: Jack Couffer and Harry Fletcher. Since the project was being overseen by the Air Force, most of the team members enlisted in the Air Force for the duration of the project and Adams promoted many of them to “acting” noncommissioned officers. Later on, Dr. Theodore Fieser, the inventor of napalm, also joined the team.

Dr. Adams and his team immediately got to work trying to find and collect bats. Dr. Adams later said “We visited a thousand caves and three thousand mines. Speed was so imperative that we generally drove all day and night when we weren’t exploring caves. We slept in the cars, taking turns at driving. One car in our search team covered 350,000 miles.” The collected several different types of bats. The largest bat that they collected was the mastiff bat, which has a twenty-inch wingspan and was able to carry up to a one-pound stick of dynamite. However, the team couldn’t find enough of them for that to be the type of bat to use. The most common type of bat collected was the common mule-eared bat which could carry three ounces, but they weren’t hardy enough to survive all the transport and poking and prodding the project required. The team selected the free-tailed bat. Though it was small, it could still fly fairly well while carrying a one-ounce bomb. The team found a colony of free-tailed bats that numbered somewhere between twenty and thirty million in Ney Cave near Bandera, Texas. According to a report by Captain Wiley W. Carr, the colony was so big and compacted that “five hours time is required for these animals to leave the cave while flying out in a dense stream fifteen feet in diameter and so closely packed they can barely fly.”

The team had three nets about three feet in diameter that were on ten foot poles. They would pass the poles back and forth across the cave entrance when the bats flew out. After only three passes with the nets, the team had collected around 100 bats. The team then took the bats out of the nets and placed them in cages in a refrigeration truck. Dr. Adams took some of them to Washington where he attached dummy bombs to them to show Army officials how the plan would work. In March of 1943, the United States Army Air Force gave authority for the experiment to proceed with arming the bats with bombs.

Dr. L. F. Fisser was given the task to design bombs that would be light enough for the bats to carry while flying. England had used firebombs in World War I that were called “baby incendiaries” that would weigh only 6.5 ounces each after being filled with a thermite mixture. Dr. Fisser designed two different bat bombs modeled after England’s baby incendiaries. The first weighed seventeen grams and would burn for four minutes with a ten-inch flame. The second weight twenty-eight grams and would burn for six minutes with a twelve-inch flame. Both bombs were oblong, nitrocellulose cases filled with thickened kerosene and had a time-delay igniter cemented onto the side of the case.

The igniter was made up of a firing pin that was held in tension against a spring by a thin steel wire. When it was time to ignite the bombs, a copper chloride solution was injected into the cavity where the steel wire passed. The steel wire would be corroded by the copper chloride. The firing pin would then snap forward and strike the igniter head, which would light the kerosene and create the firebomb.

Captain Carr described how to outfit the bats with the bombs: “Bats were taken from the refrigeration truck in a hibernated state in lots of approximately fifty. They were taken individually by a biologist and

about a one-half inch of loose chest skin was pinched away from the flesh. While this operation was being done, another group was preparing the incendiaries. One operator injected the solution in the delay mechanism, another sealed the hole with wax, and another placed the surgical clip that was fastened to the incendiary by a short string…The incendiary was then handed to a trained helper who fastened it to the chest skin of the bat.”

The Crosby Research Foundation, which was created by Bing Crosby and his brothers Bob and Larry, were tasked with creating the big bomb that would hold all of the bats and their tiny bombs. It basically looked like what we think bombs look like, a cylinder with tapered nose and fins. The exterior was made of sheet metal. The interior of the bomb contained a parachute, heating and cooling controls, and stacks of cardboard trays that could hold one thousand and forty bats. The big bat bombs would be loaded onto a plane and dropped while the plane was flying over the target area. The big bomb would automatically open up when it was about 1,000 feet above the ground and release the bats. The bats were then supposed to fly into dwellings and other structures, where they would hopefully gnaw through the string that attached the bomb to themselves before the steel wire was corroded and fly away leaving the fire bombs behind to cause mass destruction.

In May of 1943, 3,500 more bats were collected at Carlsbad Caverns and flown to Muroc Lake California. On May 21, 1943, five drops of bats wearing dummy bombs were made from a B-25, however the tests were not successful. Many of the bats had not fully come out of hibernation before the drop, so when the big bomb opened up to release them they were still asleep and fell to their deaths. After that, the research team was transferred to an Army Air Force airfield at Carlsbad, New Mexico. Problems kept arising for the bat research team. The bat skin where they were attaching the surgical clips was delicate and kept tearing, the big bat bombs weren’t opening at the right times, and they were still having problems with bats waking up on time.

The team worked through these issues and had a few successful trial runs. A mockup Japanese village was built at Utah’s Dugway Proving Grounds and the bats were released on it, causing adequate destruction. The chief chemist said of the trial run “The regular bombs would give probably 167 to 400 fires per bomb load where bats would give 3,625 to 4,748 fires.” Not all trial runs were successful though. Before one trial run, a careless handler left a door open and six bats that had been fitted with live bombs escaped their cage. The bats flew into a hangar and under a general’s car, successfully burning up both. The Army passed the project to the Navy in August 1943, and they renamed the project, Project X-Ray.

In October of 1943, the Navy leased four caves in Texas and then handed the project over to the Marine Corps. The Marines assigned soldiers to guard the caves. Dr. Adams created screens that would be placed over the cave entrances and capture the bats. Up to a million bats could be collected in one night. On December 13, 1943, experiments with bat bombs under the Marine Corps began. In total, thirty-five fires were started in the experiments. Twenty-two of those fires went out on their own and only four of the fires required professional firefighters to put them out. A more powerful incendiary would be required in order to create the fire storm that was expected.

More money and tests were poured into the project and full-scale bomber bat tests were planned for August 1944. However, it was assumed that the bats wouldn’t be ready for combat until mid-1945. When

Fleet Admiral Ernest J. King heard about the timeline, he quickly canceled Project X-Ray. In total, the project cost $2 million (around $29 million today.) It is widely believed that the real reason that Project X-Ray canceled was because the military decided to direct all available funding and resources towards the Manhattan Project. Dr. Adams was very disappointed to see his project abandoned and said that, unlike the atom bomb, his method would have caused the devastation of Japan “but with small loss of life.” Dr. Adams continued to invent and his later inventions included prairie seed bombs and a fried chicken vending machine.

The Japanese had also been working on their own fire-bomb campaign while Adams was working bat bombs. The Japanese had the fu-go plan which was to send balloons carrying bombs from Japan to the Pacific Northwest of America using the jet-stream. Hypothetically, the balloons would land in the forests and create mass forest fires along the west coast. The balloon bombs were around 33 feet in diameter and were made from rubberized silk or paper. Each balloon carried firebombs along with sandbags. Barometer-operated valves released hydrogen if the balloon gained too much altitude or dropped sandbags if it lost too much altitude. Japan released around 9,000 of these balloon bombs, most never made it to America, but at least 342 did reach the United States. Some balloons made it as far as North Dakota. One balloon hit a power line and temporarily blacked out a nuclear weapons plant in Hanford, Washington. There were six American casualties from the balloon bombs, five kids and their Sunday school teacher that were on their way to a picnic. It’s believed that there are probably still fu-go balloons in America that never ignited and are hidden in the Pacific Northwest. Some hikers found one in 2014. So if you find a huge paper lantern in the woods, just leave it alone.


“Bat Bomb: World War II’s Other Secret Weapon” by Jack Couffer

“Old, Weird Tech: The Bat Bombs of World War II” by Alexis C. Madrigal

“’Bat Bombs’: WWII’s Project X-Ray” by Allan T. Duffin

“The Bat Bombers” by C.V. Glines

“A Batman to the Rescue” by Dr. Patrick Drumm and Christopher Ovre

“Bats and Balloon Bombs: The Weird Weapons That Could Have Won WWII” by Danny Lewis

“Pearl Harbor Bombed” a article

“May 5, 1945: Japanese Balloon Bomb Kills 6 in Oregon” by David Kravets

0 views0 comments

Recent Posts

See All

Listen Here: On Christmas Eve, 1926 a man stumbled into the emergency room of a New York City hospital telling

Listen Here: In 1868, Cubans and Spain entered in what was later known as the Ten Year’s War where Cuban rebels t

Listen Here: Presidential Trivia: Instead of the bible, which book did President John Quincy Adams take his oath of o