The lemming (binomial name Lemmus lemmus) is a small rodent native to northern Scandinavia and Arctic regions. Measuring 2 to 6 inches in length, lemmings are famous for their migratory patterns during which, under pressure from increasing populations, they migrate in large numbers across the terrain. The idea that they deliberately throw themselves off cliffs committing mass suicide, long considered a myth, actually has a basis in fact, though the deaths are certainly not deliberate, merely the result of overcrowding and effectively running out of land. In the 1950s Walt Disney made a film called White Wilderness which featured thousands of lemmings apparently jumping off cliffs into the icy sea, but it later transpired that they had been pushed.
Lemming migrations have in the past reached plague-like proportions. The fear of these lemming plagues among Scandinavian villagers has led to unusual beliefs surrounding the animal. Olaus Magnus, in his 1555 Historia de Gentibus Septentrionalibus, describes the then-common belief that they bred in the clouds:
- "In the foresaid Helsingia, and provinces that are near to it, in the diocese of Upsal, small beasts with four feet, that they call Lemmar or Lemmus, as big as a rat, with a skin diverse-coloured, fall out of the ayr in tempests and sudden storms; but no man knows from whence they come--whether from the remoter islands, and are brought hither by the wind, or else they breed of feculent matter in the clouds; yet this is proved, that so soon as they fall down there is found green grass in their bellies not yet digested. These, like locusts, falling in great swarms, destroy all green things, and all dyes they bite on, by the venome of them. This swarm lives so long as they feed on new grass. Also they come together in troops like swallows that are ready to fly away; but at the set time they either dye in heaps with a contagion of the earth (by the corruption of them the avr grows pestilentiall and the people are troubled with vertigos or the jaundice); or they are devoured by beasts called commonly lekeirt or hermalins, and these Ermines grow fat thereby, and their skins grow larger."
The Danish physician Olaus Wormius, in his treatise on the Lemming in his posthumous Museum Wormianum (1655), debunked this proto-Darwinian idea of spontaneous generation by showing through dissection that lemming anatomy contained testes.
- Quoted in The Living Age, by Robert S Littell, 1873.