Norwegian lemmings go through dramatic population cycles, with their density increasing and then decreasing by a factor of 3,000:
Accounts of lemming migrations go back hundreds of years. In 1823, for instance, one explorer wrote of seeing “such inconceivable numbers” in his Scandinavian travels “that the country is literally covered with them”.
An army of lemmings advanced with extraordinary purpose, “never suffering itself to be diverted from its course by any opposing obstacles,” not even when confronted by rivers, or even the branches of narrow fjords. “They are good at swimming,” says Stenseth. “They can easily go across small bodies of water, across small lakes,” he says.
Given such sudden and apparently reckless behaviour, it is perhaps inevitable that local people in bygone centuries came to see the lemming as a crazed creature, and a swarm as “the forerunner of war and disaster”. But we have Walt Disney to thank for really embedding this stereotype in the public consciousness.
On the back of the animated classic Bambi, Disney undertook a series of ground-breaking, feature-length nature documentaries known as The True-Life Adventures. In one of these, White Wilderness, he dramatised the lemming mass suicide.
Stenseth is generous about the movie. “It is a nice film actually,” he says. “But there are some bits and pieces that are wrong with it. That [the lemming segment] is one of them.”
For a start, White Wilderness – filmed in Canada rather than Scandinavia – depicts the wrong species. Although all lemmings experience population highs and lows, the accounts of mass movements were all based on observations of Norwegian lemmings, not the brown lemmings that Disney used. He paid Eskimos “$1 a live lemming,” says Stenseth.
But that’s just the start. In an infamous sequence, the lemmings reach the edge of a precipitous cliff, and the voiceover tells us that “this is the last chance to turn back, yet over they go, casting themselves bodily out into space.”
It certainly looks like suicide. “Only they didn’t march to the sea,” says Stenseth. “They were tipped into it from the truck.”
Once you know the sequence has been faked, it makes for rather awkward viewing.
That movie-fueled myth did lead to a delightful computer game though.
My favorite bumper sticker ever was: Go Lemmings Go!