THE legendary population crashes suffered by lemmings are caused entirely by interactions with their predators and not by any limitation on food or space, according to a mathematical population model based on observations in the wild.
Scientists have long dismissed the myth that lemmings commit mass suicide when pushed for space, but argument has raged over what triggers the spectacular fluctuations in population. In the space of four to five years, lemming numbers in the high Arctic tundra of Greenland can shoot up over a hundredfold before crashing back down again.
Ilkka Hanski at the University of Helsinki, Finland, and…
