LEGEND OF THE BOILING FROG IS JUST A LEGEND
November 18, 2002
I received a communication about frogs that emphasizes the importance
of confirming conventional wisdom and offers a metaphor for the human
response to environmental degradation.
issue started with an email from Germany. As often happens in scientific
inquiry, though the answer to the question was pretty straightforward,
arriving at the answer was not. But the easy way out accepting what
"everyone knows" more often than not simply perpetuates misinformation.
Although finding an answer that destroys an urban myth or a commonly
held belief may disappoint some people, we are better off knowing the
Pechmann at the University of New Orleans, who is a noted amphibian
conservation biologist, received a query last month that read: "I
am writing a weekly column for Die Zeit, Germany's major weekly paper,
on scientific urban legends that my readers ask me about. Now you surely
have heard the story of the boiling frog that is often told by consultants
or activists: If you put a frog in boiling water, he will try to escape.
If you put him in cold water and heat it gradually, the frog will remain
in place until he's boiled, because that's the lesson, to him (and consequently
to us) gradual change is not perceivable. Frankly, I don't buy this.
But I am looking for professional advice (and I don't want to boil frogs).
Can you help me with that question? Thanks! Christoph Droesser, Hamburg,
Joe was not sure what the answer was, so he referred Mr. Droesser to
me. I also passed the buck, saying: "I have heard the anecdote
many times and actually heard a Baptist preacher give a sermon in Mississippi
in which he used the story of a big bullfrog in a bucket of water that
was being heated. The situation was presented as an example of how gradual
habituation to a devilish situation leads to acceptance of an even worse
one. But with a real frog in real water, my bet is that when it began
to get uncomfortable the frog would jump out if it could, long before
the water started to boil. Nonetheless, consultants, activists, and
others who are unaware of gradual environmental problems are responding
in the way we like to think a frog acts rather than the way it does."
went on to say, "Although I do not know a data-based answer myself,
I am aware of experiments that have been done on responses of amphibians
to thermal conditions. In some of the experiments the temperature was
gradually raised, so I feel certain someone familiar with those studies
would have an impression of what a frog would do as the water warmed
up. I am sending your question to Dr. Victor Hutchison at the University
of Oklahoma to see what he says. I would be interested to know also."
Vic's answer was as follows: "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." Naturally, if the frog were not allowed to escape
it would eventually begin to show signs of heat stress, muscular spasms,
heat rigor, and death.
So where does that leave us with the metaphor for the human response
to environmental degradation? Well the idea that you can induce a frog
to remain in boiling water if you start it off in cold water is not
true biologically. But that does not diminish the need to keep an eye
out for the gradual relaxation of environmental laws and regulations.
The metaphor lies in the frog's ability to escape from the container:
if there's no way out, then the frog's fate is a foregone conclusion.
you have an environmental question or comment, email