Over the edge

Lemmings do not rush over cliffs in their thousands, after all. Their association with the idea of altruistic suicide when their population grows too much for the tundra of Greenland to support turns out to be just another rural myth.

Never mind that we sort of knew that. Olivier Gilg and his colleagues at Helsinki University have finally pinned down the causes of the wild fluctuations in lemming numbers. They are the result of overlapping cycles of boom and bust in the populations of their four main predators. Which are - just in case this comes up when you are on Who Wants to be a Millionaire - stoats, owls, foxes and the long-tailed skua.

Science, ever restless, cannot stop there. There are other popular myths about wildlife that need debunking. Are foxes really sly, or owls wise or elephants afraid of mice? We should be careful. Dr Gilg and his colleagues put a source of vivid metaphor at risk. Where would commentary on the travails of the Conservative Party have been over the past 13 years without the lemming analogy. Not only that, but virtually the whole of children's literature is at stake, in which weasels, stoats and ferrets have been typecast as the baddies since time immemorial.

Then there is the U-rated film industry. Anyone in loco parentis who was conned into watching Finding Nemo this half-term will want a full scientific inquiry into the issues of short-term memory loss in fish, and whether seagulls are stupid. At least it is too late now for Disney to make a film about lemmings.