The Norway lemming Lemmus lemmus, is a common species of lemming

Lemming

Lemmings are small rodents, usually found in or near the Arctic, in tundra biomes. They are subniveal animals, and together with voles and muskrats, they make up the subfamily Arvicolinae , which forms part of the largest mammal radiation by far, the superfamily Muroidea, which also includes rats,...

 found in northern Scandinavia

Scandinavia

Scandinavia is a cultural, historical and ethno-linguistic region in northern Europe that includes the three kingdoms of Denmark, Norway and Sweden, characterized by their common ethno-cultural heritage and language. Modern Norway and Sweden proper are situated on the Scandinavian Peninsula,...

 and adjacent areas of Russia

Russia

Russia or , officially known as both Russia and the Russian Federation , is a country in northern Eurasia. It is a federal semi-presidential republic, comprising 83 federal subjects...

. It is the only vertebrate species endemic

Endemic (ecology)

Endemism is the ecological state of being unique to a defined geographic location, such as an island, nation or other defined zone, or habitat type; organisms that are indigenous to a place are not endemic to it if they are also found elsewhere. For example, all species of lemur are endemic to the...

 to the region. The Norway lemming dwells in tundra

Tundra

In physical geography, tundra is a biome where the tree growth is hindered by low temperatures and short growing seasons. The term tundra comes through Russian тундра from the Kildin Sami word tūndâr "uplands," "treeless mountain tract." There are three types of tundra: Arctic tundra, alpine...

 and fell

Fell

“Fell” is a word used to refer to mountains, or certain types of mountainous landscape, in Scandinavia, the Isle of Man, and parts of northern England.- Etymology :...

s, and prefers to live near water. Adults feed primarily on sedges

Carex

Carex is a genus of plants in the family Cyperaceae, commonly known as sedges. Other members of the Cyperaceae family are also called sedges, however those of genus Carex may be called "true" sedges, and it is the most species-rich genus in the family. The study of Carex is known as...

, 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.