Claim:   A frog placed in water that is brought to a boil through gradual temperature increase will make no attempt to escape.

Status:   False.

Example:   [Collected on the Internet, 1998]

There's an old folk warning that if you throw a frog in boiling water he will quickly jump out. But if you put a frog in a pan of cold water and raise the temperature ever so slowly, the gradual warming will make the frog doze happily . . . in fact, the frog will eventually cook to death, without ever waking up.

Origins:   The "boiled frog" story is indeed a kind of "old folk warning," an all-purpose didactic anecdote particularly favored by business types to illustrate the point that moving too recklessly and aggressively may leave one with an empty pot, but traversing a steadier course of more gradual change is much more likely to bring about the desired result. (One specific application might be the computer market: a PC manufacturer who comes out with an entirely new line of machines incompatible with software written for earlier models might lose a good deal of his customer base, but one who ensures that his new PCs are backwards-compatible with older software will have a much easier time inducing his customers to upgrade their hardware.) Or the story can be used in the opposite sense, to demonstrate the perils of remaining complacent in the marketplace. (A PC manufacturer too slow to upgrade his product line may not realize until too late that his market share has gradually eroded to the point that recovery is impossible.)

The fable is also used by moralists as a cautionary tale warning against the folly of letting smaller wrongs just slip by or of falling into a pattern of small and seemingly harmless sin rather than disturb one's complacency enough to address these issues, thereby allowing evil to grow into a powerful force. When used in this fashion, those being regaled with the anecdote are being cautioned against their moral inactivity or laxity leading to their someday finding themselves to be the frog engulfed in a deadly situation.

The explanation usually given why a slowly-boiled frog will complacently remain in a pan of water, even to his death, while a quickly-boiled one will try to escape, is something like the following:

I am told the above instructions work because frogs are cold-blooded. This means its body temperature is the same as the surroundings, unlike us human beings. We are warm-blooded, meaning our body temperature is kept more or less constant, and does not follow that of our surroundings. We shiver in cold weather to keep up our body temperature. We sweat in warm weather to cool ourselves down.

The frog’s body temperature follows its surroundings. If you put the frog directly in boiling water, it will sense the heat immediately and jump out. But when you heat the water slowly, the frog keeps adjusting to the rising temperature. When the heat is too much for the frog to take, it is too late. The frog collapses and dies.

Like a fable, the "boiled frog" anecdote serves its purpose whether or not it's based upon something that is literally true. But it is literally true? Not according to Dr. Victor Hutchison, a Research Professor Emeritus from the University of Oklahoma's Department of Zoology, whose research interests include "the physiological ecology of thermal relations of amphibians and reptiles to include determinations of the factors which influence lethal temperatures, critical thermal maxima and minima, thermal selection, and thermoregulatory behavior":

The legend is entirely incorrect! The 'critical thermal maxima' of many species of frogs have been determined by several investigators. In this procedure, the water in which a frog is submerged is heated gradually at about 2 degrees Fahrenheit per minute. As the temperature of the water is gradually increased, the frog will eventually become more and more active in attempts to escape the heated water. If the container size and opening allow the frog to jump out, it will do so.

Last updated:   12 January 2009

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  Sources:

    Gibbons, Whit.   "Legend of the Boiling Frog Is Just a Legend, But Does Have Environmental Value."

    Athens Banner-Herald.   12 December 2002.

    Tan, Paul Lee.   Encyclopedia of 7700 Illustrations.

    Rockville, Maryland: Assurance Publishers, 1979.   ISBN 0-88469-100-4   (p. 1445).

    Fast Company.   "Next Time, What Say We Boil a Consultant."

    November 1995   (p. 20).