Doc, Bats and Rattlesnakes in the 1930s and ’40s

by G. E. Folk

November 2, 2010

I was a biology student at Harvard University from 1933 until I got
my Ph.D. A delightful experience occurred in my senior undergraduate
year that involved Doc Edgerton and a rattlesnake. I wanted to learn
about poisonous snakes, so I had purchased a rattlesnake to keep in a
glass case.

I was introduced to Doc at MIT, probably by my sponsor,
John Welch. I knew that Doc had developed the electronic strobe light
and the ultra high-speed camera. When I mentioned the rattlesnake’s
strike to him, Doc said he would like to stop that action with his
strobe and camera. He knew that as a rattlesnake strikes, it opens its
mouth, pulls back a membrane, and protrudes the fangs, ready to inject
poison. So I took my rattlesnake in a glass case along with several
mice to Doc’s laboratory. He told me that when he pressed the
trigger on the camera, perhaps a hundred feet of film would fire
rapidly and he wouldn’t be able to stop it, so I was given the
difficult job of saying when the snake was going to strike.

The snake was very interested in the lunch we’d provided it, and
stared at the mouse, obviously deciding how and when to strike. Three
times I thought the strike would occur, but the snake did not
cooperate. Twice when I gave the alert, the film ran through the
camera but the snake didn’t strike, so the film was wasted. The
third time I said “Now!” the snake struck and drew back again so
quickly that the film had not even started running. Doc was very good
natured about all this and took out another camera to photograph the
rattlesnake as it ate its lunch, which had died instantly upon being

Several years later, when I was a graduate student, my friend and
colleague, Hermann Rahn, sent Doc another rattlesnake, this time from
Wyoming, so that they could use the stroboscope to measure the
frequency of the rattlesnake’s tail as the snake gave its signature
warning. I know they were successful, though I’m not sure what the
frequency of the rattle was.

At around the same time, another good friend of mine, the brilliant
scientist Donald Griffin, worked with Doc to “stop the flitting
shadow which is a bat and show, in clear photographs, exactly how it
uses its wings” (Griffin 1946, p. 117, see below). In the article,
Don described the experience of working with Doc to photograph the
bats, as well as Doc’s ingenuity in devising a system to capture the
shots. The findings—bats flap their wings 15 times per second and
fly about 10 m/h—and three of Doc’s photographs were published in
Don’s fascinating article, “Mystery Mammals of the Twilight,”
National Geographic, July 1946, pp 117-134.

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