Friday, October 31, 2003

Myth of lemmings' suicide is driven over the cliff

The Times, London, 31 October
Myth of lemmings' suicide is driven over the cliff
By Stephen Brook


SCIENTISTS have solved one of the world’s great mysteries. The reason lemmings suicidally hurl themselves over cliffs is that. . . they don’t.
The myth arose because of sudden, severe falls in the population of the hamster-like rodent. Scientists have long been puzzled by the four-year cycle of boom and bust, which would see the Arctic tundra teeming with lemmings one year, only for them to disappear almost completely the next. They blamed changes in food supply and habitat while almost everyone else put it down to mass suicide.

But yesterday researchers pinned the blame on a quartet of Arctic predators: the arctic fox, the snowy owl, the stoat and the long-tailed skua. “It’s been an unsolved question for 80 years,” Olivier Gilg, a researcher at the University of Helsinki, said.

Dr Gilg and his colleagues studied the collared lemming in Greenland’s high Arctic tundra for 15 years and published their research in the journal Science yesterday.

They found that when the lemming population increased, so did the numbers of foxes, owls and skuas. The stoats took a year to catch up, because of slower reproduction.

By the time they did, the number of predators feasting on the lemmings drove their numbers down. Then the foxes, skuas and owls moved on to other prey, but the stoats ate only lemmings and died away — starting the cycle again.

Dr Gilg said the myth of mass suicide lay with an unlikely villain — Walt Disney. Lemmings sometimes fell over cliffs during chaotic mass migrations. But the 1958 Disney documentary White Wilderness is said to have faked footage of them rushing en masse for the nearest cliff and hurling themselves over.

“If a Walt Disney documentary presented it as lemming suicide, then it must have been true,” Dr Gilg said.