The frog in boiling water

Al Gore, in his film "An Inconvenient Truth," repeats an old urban legend about a boiled frog.

The premise of the story is that a frog placed in a slowly-warming body of water cannot sense the change, and will not hop out even as the temperature becomes too great for safety. The frog, being ectothermic, will merely continue to feel only the same comfort as ever, while its body warms along with its environment.

One problem with this fable is that it's not logical. A frog's body is not insensitive to a change in temperature, just because it is ectothermic. Evolution would not allow that — and a frog would not live long if that were true.

Another problem is that the story is untestable in the context of a politically-astute discussion.

You boiled a frog, slowly? Thanks for the metaphor.

You didn't? Then who did, and where are the data?