Lemmings (Arvicolinae subfamily) are rodents related to voles and muskrats. There are over 100 species of lemmings and all are native to far northern tundra biomes near the Arctic Circle. There is a common misconception that lemmings are unintelligent animals that frequently commit mass suicide during migration by jumping off of cliffs.
Most lemmings are three to six inches in length and weigh less than four ounces. They have soft fur and short tails, and like all rodents have perpetually-growing incisor teeth. Lemmings feed mainly on leaves, grasses, shoots and bulbs, occasionally storing food for winter use. Lemmings live in simple underground burrows and are very solitary, only interacting with each other for mating purposes.
Unlike some other northern mammals, lemmings do not hibernate and can stay active year round. This constant activity combined with a very short breeding cycle can lead to population booms and crashes in some species. For example, the Norway lemming reaches sexual maturity at one month old and can produce a litter of six to eight young every three weeks year round if weather is good. This can lead to a larger lemming population than the area can support, resulting in mass mortality and a population crash. This crash and boom cycle happens every 3-4 years.
When an area can no longer support a population, some species of Scandinavian lemmings will scatter in all directions in search of food and shelter. These mass migrations may cause the death of many lemmings from falls or drowning in bodies of water that are too large to swim across. This behavior has lead to the myth that lemmings are suicidal, when in fact they are merely searching for habitat and trying to survive.
- The range of prairie owls which use lemmings as a food source moves south whenever the lemming population crashes.
Smithsonian National Museum of Natural History Arctic Studies Center
Alaska Department of Fish and Game