Norway, Sweden, Finland, extreme north west Europe.
Biogeographic Regions: palearctic (Native )
Average mass: 70 g.
Average basal metabolic rate: 1.071 W.
Habitat and Ecology
Alpine, tundra, steppe, temperate grasslands, scrub, open forest, rocks.
Terrestrial Biomes: tundra ; savanna or grassland ; mountains
Herbivorous, diet consisting largely of berries, leaves, grasses, bark, lichens, roots, green part of plants, bulbs, mosses, pine needles. Forage both day and night. Graze and dig for roots.
Life History and Behavior
Status: captivity: 2.0 years.
Lifespan, longevity, and ageing
Gestation 16- 28 days. Reach sexual maturity early (females: 2-3 weeks old, males: 6-8 weeks old). Very fecund. Breed in summer and winter. Length of breeding season varies. Mated female may fail to conceive or may abort if exposed to a strange male. Litter size may vary from 1-12 or more litters per year. Some females genetically programmed to bear only female offspring.
Average birth mass: 3.8 g.
Average gestation period: 19 days.
Average number of offspring: 7.
Average age at sexual or reproductive maturity (male)
Sex: male: 44 days.
Average age at sexual or reproductive maturity (female)
Sex: female: 24 days.
Evolution and Systematics
Norway lemmings emigrate en mass in search of food once their population size reaches 40-100 individuals per acre.
"One much smaller species of herbivorous mammal that still undergoes periodic swarming on a spectacular scale is the lemming. Displaying a formidable reproductive rate - more than 100 offspring can be born to a single pair within six months - a population of Norwegian lemmings (Lemmus lemmus) can expand very dramatically. In doing so, the lemmings deplete their food supply within a given area of the Scandinavian tundra and scrub that comprises their normal habitat. Once the population size reaches 40-100 individuals per acre (100-250 individuals per hectare), which tends to occur every three to five years, emigration ensues, whereby a sizable horde of these volelike rodents travels southward in search of food, expanding their population's range by 120 miles (200 km) or more as they go." (Shuker 2001:78-79)
Learn more about this functional adaptation.
- Shuker, KPN. 2001. The Hidden Powers of Animals: Uncovering the Secrets of Nature. London: Marshall Editions Ltd. 240 p.
Molecular Biology and Genetics
Statistics of barcoding coverage: Lemmus lemmus
Public Records: 0
Specimens with Barcodes: 3
Species With Barcodes: 1
IUCN Red List Assessment
Red List Category
Red List Criteria
Many live in areas of little agricultural importance to humans. Not pests. Not endangered. Highly varying population density (see "Other Comments"). Clearing of forests by humans has increased habitat.
IUCN Red List of Threatened Species: least concern
Relevance to Humans and Ecosystems
Economic Importance for Humans: Negative
Some harbor vectors of disease, such as plague.
Economic Importance for Humans: Positive
Social behavior studied by many.
The Norway lemming, also Norwegian lemming (Lemmus lemmus) is a common species of lemming found in northern Fennoscandia. It is the only vertebrate species endemic to the region. The Norway lemming dwells in tundra and fells, and prefers to live near water. Adults feed primarily on sedges, grasses and moss. They are active at both day and night, alternating naps with periods of activity.
The Norway lemming has a bold pattern of black and yellow-brown, which is variable between individuals. It grows to a size of 155 mm. The tail is very short (10 - 19 mm). It weighs up to 130 g. The dental formula is 1/1, 0/0, 3/3.
The Norway lemming has a dramatic three- to four-year population cycle, in which the species' population periodically rises to unsustainable levels, leading to high mortality, which causes the population to crash again.
The Norway lemming spends the winter in nests under the snow. When the spring thaws begin and the snow starts to collapse, they must migrate to higher ground, where the snow is still firm enough for safety, or, more commonly, to lower ground, where they spend the summer months. In autumn, they must time their movement back to sheltered higher ground carefully, leaving after alpine snow cover is available for their burrows and nests, and before the lowlands are made uninhabitable by frost and ice.
When the seasons are particularly good (short winters without unexpected thaws or freezes, and long summers), the Norway lemming population can increase exponentially: they reach sexual maturity less than a month after birth, and breed year-round if conditions are right, producing a litter of six to eight young every three to four weeks. Being solitary creatures by nature, the stronger lemmings drive the weaker and younger ones off long before a food shortage occurs. The young lemmings disperse in random directions looking for vacant territory. Where geographical features constrain their movements and channel them into a relatively narrow corridor, large numbers can build up, leading to social friction, distress, and eventually a mass panic can follow, where they flee in all directions. Lemmings do migrate, and in vast numbers sometimes, but the deliberate march into the sea has yet to be verified.
According to genetic research, the Norwegian lemming survived the Pleistocene glaciation in western Europe, inhabiting various refugia which were not covered by ice. Alternatively, some researchers have contended the Norwegian lemming populations had arisen from ancestors of the present-day brown lemming (Lemmus sibiricus), moving in after glaciers receded.
- Henttonen, H. (2008). Lemmus lemmus. In: IUCN 2008. IUCN Red List of Threatened Species. Retrieved 5 June 2009. Database entry includes a brief justification of why this species is of least concern.
- MacDonald, David; Priscilla Barret (1993). Mammals of Britain & Europe 1. London: HarperCollins. pp. 241–242. ISBN 0-00-219779-0.
- Fedorov, V.B. & Nils Christian Stenseth (2001). Glacial survival of the Norwegian lemming (Lemmus lemmus) in Scandinavia: inference from mitochondrial DNA variation. Proceedings of the Royal Society: Biological Sciences, 268(1469):809-814.