Do lemmings really commit mass suicide? Moralist, keen to discover lessons for humanity in the behavior of animals, have often perpetrated myths that give a very distorted picture of the natural world. For example, medieval bestiaries, books that treated animals and their behavior as allegorical fables with a Christian message, describe a mother pelican pulling the flesh and blood from her own breast to feed her young. This sacrifice was meant to illustrate Christ’s own sacrifice for mankind. No pelican, of course, has ever made a heroic gesture of this kind
A lesson from man
Today moralist sometimes seize upon the legend of lemmings rushing headlong over cliffs into the sea to draw a parallel with the problems of human overpopulation. According to this legend, lemmings deliberately give their lives to prevent their species becoming extinct through overpopulation.
It is true that roughly every four years, lemmings, like other small rodents that inhabit the arctic tundra, suffer a dramatic population explosion. The consequences of these explosions are far-reaching, especially in the case of the Norway lemming, the species that gave rise to the legend.
Search for food
The lemmings wear away the sparse tundra vegetation by overgrazing and by digging tunnels and burrows. So each spring and autumn, they migrate singularly or in small groups in search of better feeding.
Every three or four years they embark on much longer mass migrations. Just what triggers the spectacular population movements is not yet clear. It may simply be starvation, although some scientists think it is stress from the overcrowding of their environment.
The search for a new home often takes lemmings as far as the sea, but they do not throw themselves in droves off cliffs. In fact, they can swim quite well and often cross fjords and lakes in the course of their journey.
However, although lemmings do not commit mass suicide, it is true that many do perish during the course of their migrations. Since they cannot swim for more than 15 to 20 minutes, many inevitably become exhausted and drown while attempting to cross the large stretches of water.