True lemming
Head and body is 10-13.5 cm, and tail length is 18–26 mm.Unlike the collared lemmings, their coats do not change color in winter.These lemmings are found predominantly in tundra or high elevations.These intense population booms appear to be most common in the northern part of its range (such as Lapland).When conditions are favorable, these demographic parameters allow for a veritable explosion in population size.