Carlsbad Caverns, NM.

In December 1941 a Pennsylvanian dentist on holidays in New Mexico, was enjoying exploring the famous caves of Carlsbad Caverns. Dr Lytle S Adams was very impressed by the activity of about a million bats flying around in the dark in the caverns that were their home. He was still vacationing at Carlsbad on the evening of the 7th when news came through about the surprise Japanese bombing of Pearl Harbour. Adams, like every patriotic American was shocked and appalled at the attack, but unlike most every other private citizen, Adams decided, more or less immediately, to actually do something about it.

The small town dentist from Irwin, Pa. devised a plan of action…within one month he submitted a seemingly preposterous proposal to the White House – Adams proposed using bats as flying incendiaries to hit back at Japan in its own cities! An apparently hare-brained notion like this from a suburban dentist could normally be expected to receive short shrift from bureaucrats and military authorities, but Dr Adams had some special connections, he was a friend of the First Lady, Eleanor Roosevelt. This guaranteed Adams’ proposal would get a good official hearing from the Military, and eventually (through a recommendation from leading zoologist Donald Griffin) the approval of President Roosevelt.

The right bat for the operation
Adams reasoned that radar-guided “bat bombs” would wreak havoc when dropped on Japanese cities because the buildings and other structures were made largely of wood, bamboo and paper. The idea you would think, to most reasonable ears, would sound ‘batty’! Adams however can’t be accused of not doing his homework…he researched the subject of bats extensively, eventually selecting the Mexican or Brazilian Free-tailed Bat (Tadarida Brasiliensis), highly prevalent in the southern regions of the US, as the optimal candidate for the task.

Mexican F-tailed Bat-cave, Carlsbad

What made the Mexican bat an attractive choice to Adams and his team of field naturalists (and to the NDRC – National Defense Research Committee) was that it weighed only ⅓ of an ounce, but could carry three-times its weight (one ounce!) Other biological factors in favour of using bats as carriers was that they occurred in large numbers, their proclivity towards hibernation and dormancy meant that they didn’t require food or maintenance, and their capacity to fly in darkness and locate dark, secluded niches to hide in during daylight [‘Bat Bomb Video’, www.wizscience.com].

Destruction by weaponised bats – the theory
The US Military embraced Adams’ idea and developed a strategy to weaponise the bats: attaching micro-incendiary devices to thousands of captured bats…the Pentagon boffins devised canisters (each had compartments housing up to 1,000 hibernating bats) to transport the bats in. B-24 Bombers would release the canisters over Japanese industrial cities initially in the Osaka Bay area of Honshu at 1000 feet. The casings would break apart at high altitude, the now awake bats would scatter and roost in dark recesses of buildings all over the city. The bats, attached to the micro-bombs by surgical clips and some string, would bite through the string and fly off. The time-activated explosives would then cause countless fires to break out all over the targeted city [Anders Clark, ‘NAPALM BATS: the Bat Bomb!’, 3-Mar-2015, Disciplines of Flight, www.disciplesofflight.com].

B-27 Liberator flying over Carlsbad National Park

Bat bomb trial-and-error
The Military labelled the bat bombs Project X-Ray and soon got down to testing Adam’s secret weapon. The first bat test the Army conducted was in May 1943 in California. Several thousand bats collected from New Mexico were induced into hibernation and then dropped from a refrigerated aircraft using dummy bombs. Unfortunately things did not go to plan…many of the bats didn’t wake from their hibernation and merely crash-landed on California soil, while only some of them managed to fly away. The attrition rate for the Army’s test bats was accordingly high. Altogether over the Project’s lifespan around 6,000 bats were used in the Bat Bomb tests (about 3,500 of these were collected from the Carlsbad Caverns) [CV Glines, ‘The Bat Bombers’, Air Force, Oct 1990, 73(10); Clark, op.cit.]

1943: Army Bat Bomb test goes haywire!

The location got changed to an Army auxiliary airfield near Carlsbad (easier access to the seemingly inexhaustible supply of bats from the caverns). Eventually the Army loaded the bats with explosives to trial some live runs. Again the bats performed erratically as glide missile pilots but this time with unintended and negative results…an Army aircraft hangar caught fire, as did a car belonging to an Army general [Clark, op.cit.]. Disillusioned by the reverses, the Army hand-balled the Project on to the Navy and Marine corps.

The Marines and the Japanese Village
The Marine corps in particular took on the renamed “Project X-Ray” with some enthusiasm…after several encouraging tests the test site was moved to the Dugway Proving Grounds in Utah, where a mocked-up Japanese Village had been created in 1943✱. The Dugway tests went better than the earlier ones, according to the testers “a reasonable number of fires” were successfully ignited, and a NDRC observer present commented that “It was concluded that X-Ray is an effective weapon”.

Dugway Proving Grounds, Utah

Tests at the Dugway, Utah, site continued in 1944 with the Marine corps believing that the Bat Bomb Project could be deployed against Japan by mid-1945. The Navy hierarchy however was unhappy at the prospect of a delay of another twelve months-plus and canned the project altogether. The US subsequently focused on bringing the atomic bomb to a state of readiness, and the outcome of those efforts altered the course of both the war and of postwar history.

Dentist-inventor Adams was extremely disappointed when the Military pulled the plug on the project. Adams maintained that what happened with the atomic devastation of Hiroshima and Nagasaki could have been avoided if the US had stuck with his bat-delivered bombings: (would have caused) “thousands of fires breaking out simultaneously … Japan could have been devastated, yet with small loss of life” [‘Top Secret WWII Bat and Bird Bomber Program’, 6-Dec-2006, www.historynet.com].

PostScript: Project Pigeon, BF Skinner’s birds of war
Before the idea of bat-bombing Japan briefly captured the imagination of the US defence establishment, serious consideration had already been given to weaponising pigeons to be used in warfare! The notion was first mooted by influential, pioneering US behavioural psychologist Burrhus Frederic Skinner in 1939. Skinner believed that the humble feral street pigeon, Columba livia domestica, had the innate attributes (excellent vision and extraordinary manoeuvrability) to be trained to guide glide missiles. The behaviourist utilised his technique of operant conditioning to train the birds by rewarding them for pecking a moving image on a screen which accurately steered the missile they were piloting towards their intended target✫ (and unfortunately also towards their own destruction!)

BF Skinner’s pigeons of war

Skinner got some backing from business and the NDRC for Project Pigeon (as it was called), and he was able to demonstrate success with trained pigeons, however the government/military was never more than at best lukewarm on the Project…ultimately by 1944 the Military abandoned the Pigeon Missile because of concern that its continuation would divert crucial funds away from the “main game”, the construction of an atomic bomb. In 1948 the Navy revived the Project, now renamed Project Orcon but in 1953 it was dumped for good when the superiority of electronic guidance systems was established [Joseph Stromberg, ‘B.F. Skinner’s Pigeon-Guided Rocket’, The Smithsonian, 18-Aug-2011, www.smithsonianmag.com; ‘Project Pigeon’, https://en.m.wikipedia.org/wiki/Project_Pigeon].

Footnote: the US Military’s experiments on bats and pigeons were classified and conducted covertly under a wartime information blackout. They would not of course have been condoned by the American Humane Society (for the welfare of animals) had the organisation known of them.

▦ See also related blog JUNE 2017 on USA/Japan conflict in World War II: Project Fu-Go: Japan’s Pacific War Balloon Counter-Offensive

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✱ two mock-up enemy villages were constructed on this same site side-by-side, a Japanese one and a German one
✫ Skinner, also an inventor, devised a nose cone (attached to a explosives warhead) in which up to three pigeons could perch and pilot the missile’s trajectory