Yesterday at lunchtime, I stopped by at the office of my friend Heather, who was screaming and running when I walked in. Evidently a scorpion had gotten behind her desk and freaked her out, and some of the guys were taking it out to kill it. The thing was huge, too, at least five or six inches long.

What I didn’t get to see was this: apparently the guys took the scorpion out, made a ring of gasoline around it and lit the gasoline ring on fire, panicking the scorpion so much that it committed suicide by stinging itself with its own venom. Mouth hanging open, I said, ‘What?’ Nobody else in the room seemed surprised, and said they were familiar with the old desert wisdom that says that scorpions are one of the few creatures on earth that commit suicide when confronted with their fear of fire. I’d never heard of this! The only creature I’d ever heard commits suicide with any regularity is the lemming, which I was fairly sure could be a myth, encouraged by the old video game. A part of my daily radio show is a segment called Croaklore, verifying the truth or falsehood of folklore and urban legends, so I was instantly interested in this idea of scorpion suicides (and was only sorry to have missed the live experiment that was conducted right outside the door!).

In 1887, the Royal Society published a piece by a Professor of Biology at the Presidency College in Madras, Alfred G. Bourne, called The Reputed Suicide of Scorpions. In it, he says:

The legend that a scorpion when placed within a ring of red-hot embers will, after making futile efforts to pass the fiery circle which surrounds it, deliberately kill itself by inflicting a wound with its sting in its own head is said to emanate from Spain, and is of considerable antiquity: it has been, morever, attested by very high authority. The phenomenon would, however, be so extraordinary that its occurrence has been much doubted. Did it happen, it would stand as Romanes says “as a unique case of an instinct detrimental alike to the individual and to the species.”

That’s for sure. A creature with a brain the size of a scorpion’s would be acting on instinct, not on thoughts. But having such instinct doesn’t make sense: there is a sound evolutionary reason that animals, by and large, don’t have the instinct to kill themselves. The creatures which have survived until the present day are those who are not so easily dissuaded from the task of living! Moreover scorpions have been around as a species for a very long time – they’re virtually a living fossil – so their instincts would have to be good.

The article goes on to list all of the scientists of the time who had observed scorpions committing suicide for themselves, giving them cause for much confusion. There have been some considerable horrors throughout the scorpion’s 430 million-year existence. Surely a creature that commits suicide when it’s afraid could not have lasted through them all? Many species which don’t possess the propensity to kill themselves have gone extinct for various reasons, yet the nervous scorpion, who pops itself at the drop of a hat, outlasts them all?

Actually, the modern scientific consensus on ‘scorpion suicide’ is that it’s impossible, due to the fact that scorpions appear to be immune to their own venom. Ten years ago, some French biologists studied the scorpion immune system and concluded:

The muscular and nervous systems of scorpions are not affected by the molecules contained in scorpion venom. [The Journal of Experimental Biology, 1998.]

Well, that’s that. So what’s happening, then? What did Heather’s scorpion do yesterday when it was surrounded by fire? Well, the best explanation being offered by people who have studied this behavior is that the scorpions are simply succumbing to the heat. Despite being known as ‘hot weather’ creatures, they’re very sensitive to heat and will die when subjected to high temperatures. They writhe on the ground trying to sting all around them (their defense mechanism), and die very quickly in those circumstances; to observers it can appear as though the scorpion is stinging itself.

Scorpion suicide? Busted.

(By the way, I love the final paragraph of that paper: “We thank Professor Robert H. Rochat for his constant interest and for supplying scorpions and venoms.” He was very excited.)