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II. Bats Away!

July 2024
5min read

It is early 1945. An American bomber crew is anxiously nearing the now familiar islands of the Japanese Empire. Flak begins to burst around the plane as the target comes into view. The bombardier releases the payload, and the crew watches as thousands of incendiary bats plummet toward the paper cities of Japan.

This bizarre event never actually occurred, but it very well could have—largely through the enthusiasm of an unlikely war planner by the name of Lytle S. Adams, a Pennsylvania dental surgeon. It seems he was on his way back from a visit to Carlsbad Caverns, New Mexico, when he learned of the Japanese attack on Pearl Harbor. He immediately thought of the millions of bats that lived in Carlsbad: why not arm the little beasts with tiny incendiary bombs? The following January he somehow got the ear of President Franklin Roosevelt and convinced him that the idea warranted investigation.

Next Adams approached Dr. Donald R. Griffin, a distinguished Harvard zoologist. Griffin was intrigued by the concept and agreed to accompany Adams on a return trip to the bat caves of Carlsbad.

The pair arrived late in July, 1942, and covered the entrance to the cave with netting wire. This snagged some five hundred of the Mexican free-tailed bats, which were transferred to coldstorage chests. The low temperature, it was hoped, would impel the bats to hibernate, thus making transportation easier and eliminating bothersome feeding. Unfortunately the system did not work too well, and only about three hundred bats survived the flight back to Cambridge. There Griffin found that the surviving bats could be kept in hibernation for a period of up to two weeks at a temperature of 10 degrees Centigrade and that each could carry a weight of three to five grams.

By this time the National Defense Research Committee had become acquainted with the “Adams Plan,” so much so that Earl P. Stevenson, a top NDRC official, suggested that bats could conceivably be released from submarines as well as from bombers. Stevenson was of the opinion that the use of bats would be very demoralizing, especially when used against a “superstitious people.”

Toward the end of 1942 the Adams Plan bogged down in bureaucratic indecision. The main drawback was the fact that Griffin’s preliminary experiments indicated bats could carry only a slight weight. But when later tests showed that the creatures could support fifteen to eighteen grams, the Army Air Force asked to push ahead with the bat bomb. So the Army’s Chemical Warfare Service and the NDRC joined forces on the project.

The incendiary unit was produced by a noted Harvard chemist, Dr. Louis F. Fieser, who was also an NDRC consultant. With a celluloid case threequarters of an inch in diameter and two and one-half inches long, the bomb was shaped so it could easily be dragged into a small crevice. It was filled with a concentrated napalm gel, equipped with a fifteen-hour delay mechanism, and attached to the loose skin of the bat’s chest with a surgical clip and a string. Moreover, Dr. Adams had designed a case that would slow the falling of the bats as they were dumped from the plane, allowing them to recover from hibernation gradually. Once fully awake, they would supposedly seek refuge in buildings, gnaw through the strings, and leave the incendiary units behind.

The first experiments, conducted at Muroc Lake, California, on May 15, 1943, were an unadulterated disaster. Fieser, Adams, and their associates found that the bats were harder to capture, more awkward to handle, and more difficult to force into hibernation than anyone had expected. Adams’ container did not sufficiently slow the descent: many bats broke their wings, and some never awakened at all. And all the bombs were too heavy. Luckily the bats released from the plane were not armed with incendiary units. Much to the chagrin of Adams and Fieser, however, the units were tested. Several bats on the ground that had incendiaries attached to them managed to escape. The hangars and outlying buildings of the small airport, as well as a general’s automobile, were the first victims of the American bat bomb.

After the May 15 fiasco, many recommended scrapping the project; indeed, no work was done on the delay device between May and September of 1943. Finally Dr. Harris M. Chadwell, chief of the NDRC’s Division 19—which handled the development of the delay mechanism—wrote Fieser that “it would be unwise for NDRC to spend any more time, money, and effort on the bat problem unless NDRC’s aid was solicited by some recognized branch of the service.”

Not wishing to see his brainchild cast aside, Dr. Adams began a vigorous public relations campaign. He explained to every general or admiral who would grant him an interview that bats are very robust and strong in any season except spring, when the tests had been conducted. Though the Army had given up hope on the bat bomb, Adams succeeded in attracting the attention of the Navy. In October, 1943, Rear Admiral D. C. Ramsey, the chief of the Navy’s Bureau of Aeronautics, asked the Chemical Warfare Service and the NDRC to keep going with the Adams Plan.

Problems soon arose, not the least of them the confusion among those working on the bomb. Because of the project’s highly secret nature (even today the blueprints of the incendiary unit remain security classified by order of the CIA), researchers struggling with one aspect of the device were unaware of the activities of their counterparts. Adams himself turned out to be a problem, too. In December, 1943, Dr. William G. Young, a UCLA chemist and NDRC consultant, complained that the dentist skipped an appointment with him on November 19: “He did not arrive either that day or the next; and at the time I phoned his home I learned that he had left at five o’clock in the morning for parts unknown. Apparently, he just chases around from one part of Southern California to another without staying put long enough for anyone to corner him.

“Last Saturday Lieutenant Charles J. Holt of the Marine Corps Air Station at El Centra came to Los Angeles to see me, and we had a very interesting talk. … Everyone in the project seems to be in agreement that Adams cannot accept responsibility for the project and have it function. For example, he ordered Lieutenant Holt to prepare for a test to be held on the desert in which ten thousand assemblies were to be used. When Holt pointed out the tremendous hazard involved to the whole of Southern California by such a program, Adams was most indignant, and the lieutenant finally had to tell him that such an experiment would not be performed even if he, Holt, had to stand in front of the arsenal with a machine gun to prevent it.”

By the middle of December, Adams had been squeezed out of the Adams Plan—which the Navy then renamed “Operation X ray.” Further tests, held at the Dugway Proving Grounds in Utah on December 15, were quite promising. In fact, on a weight-to-weight basis, the tiny bat incendiary was more effective than any other such bomb in our arsenal; one estimate had it that a typical planeload of bat bombs would set anywhere from 3,625 to 4,748 fires, as opposed to from 167 to 400 with a planeload of regulation incendiaries.

It finally seemed that the time had come to use the bat bomb against Japan. The last day for all design changes was March 15, 1944; extensive tests of the finished product were scheduled for late April, and large-scale production, as many as 1,000,000 units, was set to begin in May.

But then, in March, 1944, Operation X ray came to an abrupt end, twenty-seven months and $2,000,000 after its conception. After the war, rumor had it that X ray had been terminated for fear the Japanese would charge the United States with having waged biological warfare. In fact, the chief of naval operations called a halt to X ray because of what he termed the “uncertainties” surrounding the behavior of the bats and the length of time before an actual strike could be launched.

So the bats of war never got there.


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