![]() The statistical clue to understanding the cycle is stoat numbers, which take a delay of about a year before falling in response to a lemming crash. The three other predators are 'generalists' - they like to tuck into lemmings but also have alternative nutrition. It is a four-year 'boom and bust' cycle whose key is the stoat, a specialist predator whose only source of food is the lemming. what is interesting in this case is that, with the lemmings, the pattern is almost like clockwork. The next phase is that the lack of lemming drives down the predator numbers. That, in turn, boosts the predator numbers, which become so numerous and gorge so much on the lemmings that the rodent numbers plummet dramatically. The researchers found that the population of lemmings and their cousins, the vole, can explode by 100 or even 1,000 times their original size. Lemming populations, say, surge spectacularly and fall just as quickly, thanks to the combined feasting of four predators: the stoat, arctic fox, snowy owl and a seabird called the long-tailed skua. Olivier Gilg of the University of Helsinki in Finland and colleagues publish their research in today's issue of the journal Science. "One of the oddest phenomena in the natural world - the sudden mass death of lemmings - has been resolved, according to a trio of European biologists. Now for the article (written October 31, 2003). and, for no particular reason, a picture of a much cuter baby squirrel (from this site): In any case, this article discusses an alternate, more plausible, explanation for the dramatic population swings that really do occur.įirst, the obligatory picture of a lemming (from the article): (I've heard that this myth originated with a Disney film, but that could be a myth too.) ![]() Lemmings are most famous for their alleged tendency to commit mass suicide by jumping off cliffs when their numbers become too great. I don't consider lemmings particularly cute as rodents go, but they can be comparatively interesting.
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