The Norway lemming (also Norwegian lemming), Lemmus lemmus, is a common species of lemming found in northern Scandinavia and adjacent areas of Russia. 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.