Time Capsule

Many psychologists remember the late Donald R. Griffin’s contributions to the study of animal thinking and consciousness. He was the biopsychologist who coined the term cognitive ethology, one of at least two terms he invented in his long and distinguished career. He is perhaps best known now for his work on animal cognition and for bringing considerable clout to the 1970s debate on the potential of studying nonhuman minds.

However, the groundbreaking work that began Griffin’s career in the late 1930s is perhaps less well known today: He was the first to confirm that bats navigate using sound. Working with George Washington Pierce and Robert Galambos at Harvard, Griffin solved the long-standing mystery of bats’ remarkable ability to navigate in the dark. The bats emitted ultrasonic cries and heard the reflected sound waves to pinpoint objects in their flight path. Griffin called the bats’ sensory-acoustic form of navigation echolocation.

The discovery of echolocation by bats opened up new research avenues in psychology, including studies of echolocation by humans. Griffin’s breakthrough and position at Harvard University’s Psychoacoustic Laboratory established him as one of the leading U.S. experts on bats. As such, in 1942 he was asked to evaluate a proposal that had made its way to the National Defense Research Committee (NDRC).

The proposal came from a Pennsylvania dental surgeon, Lytle S. Adams, who had witnessed millions of bats as they flew out at dusk from Carlsbad Caverns shortly before he heard on his car radio of Japan’s attack on Pearl Harbor. An outraged Adams concocted a plan to retaliate against the Japanese: tapping bats’ natural behavior to counterattack Japanese cities.

When Griffin received the proposal, he was working as an assistant in S.S. Stevens’s lab. Stevens was the Harvard psychologist known for introducing the scales of measurement commonly used in modern statistics and for proposing the psychophysical principle known as Stevens’ Power Law. After consulting with Stevens, he considered the feasibility of Adams’s proposal, which called for thousands of bats — each carrying a small time-delay incendiary explosive attached to its body — to be released at night by airplanes flying over Japanese cities. As they sought shelter for the day, the bats would roost in the nooks and crannies of the wood frame buildings so common in Japanese urban centers, igniting thousands of fires and creating chaos that would cripple Japan. In April 1942, Griffin wrote the following summary evaluation for the NDRC:

“This proposal seems bizarre and visionary at first glance, but extensive experience with experimental biology convinces the writer that if executed competently it would have every chance of success.”

Griffin went on to recommend some intermediate steps, including locating bats that might serve in the mission, determining their load-bearing capacity and how best to attach the incendiary devices, and ascertaining the best means of transporting and releasing the bats. Griffin even followed up personally on one of his recommendations. He collected a sample of Mexican free-tailed bats at Carlsbad Caverns to test their load-bearing abilities back at Harvard. The curious young Griffin even checked one bat’s weight-carrying capacity in his motel room three hours after capturing it.

Soon, the Adams proposal was given a green light — somewhat surprising given the considerable obstacles that B.F. Skinner fought to overcome in developing his pigeon-guided Pelican bombs at about the same time. The difference was that Lytle Adams had friends in high places. Adams knew Eleanor Roosevelt, and had flown her in his own plane to see demonstrations of one of his earlier and quite successful ideas — an airmail pickup system that did not require the pickup plane to touch down. So, when Adams detailed his incendiary bat proposal in a letter to President Franklin D. Roosevelt, his name was already known in the White House. The president was sufficiently impressed to forward the proposal with a personal recommendation to investigate the idea further.

The president’s memorandum stated: “This man is not a nut. It sounds like a perfectly wild idea but is worth looking into.”

Griffin’s involvement in the project ended when data from his sample of bats indicated that they could not carry the weight of the incendiaries. His findings were disputed and research and development continued, conducted first by the Army, then by the Navy. Harvard’s Louis Fieser, an incendiary chemist and the inventor of napalm, developed suitable miniature time-delay incendiaries for the project. Several field tests took place, and in one mishap, an auxiliary airfield sustained severe fire damage from incendiary bats. Specially designed bomb casings to carry incendiary bats were actually manufactured for American bomber planes in a factory owned by celebrity crooner Bing Crosby. However, like Skinner’s Project Pelican, the incendiary bat project ended when the atomic bomb became a research priority. Explosive bats were never deployed in an attack on Japan.

When a more mature Griffin became a proponent of consciousness in nonhumans, he questioned his support of weaponizing bats on ethical grounds. He believed that wartime mentality compelled him to support the project in his youth and he would not have supported it with the mind set he held later in life.

The “bat bomb” saga stands as an example of contextual forces influencing the thinking of a scientist, and it remains an intriguing episode in the history of World War II.


Patrick Drumm, PhD, is an associate professor of psychology at Ohio University Lancaster and Christopher Ovre is a graduate student at Ohio University’s main campus in Athens. Katharine S. Milar, PhD, Earlham College is the historical editor for “Time Capsule.”

Suggested reading

  • Couffer, J. (1992). Bat bomb: World War II’s other secret weapon. Austin, TX: University of Texas Press.

  • Griffin, D.R. (1958). Listening in the dark: The acoustic orientation of bats and men. New Haven, CT: Yale University Press.

  • Griffin, D.R. (1976). The question of animal awareness: Evolutionary continuity of mental experience. New York: The Rockefeller University Press.

  • Griffin, D.R. (1992). Animal minds: Beyond cognition to consciousness. Chicago, IL: The University of Chicago Press.

  • Griffin, D.R., & Galambos, R. (1941). The sensory basis of obstacle avoidance by flying bats. Journal of Experimental Zoology, 86, 481-506.

  • Skinner, B.F. (1960). Pigeons in a Pelican. American Psychologist, 15, 28–37.