The lemming is a small, stout rodent native to the circumpolar regions of the Arctic. They primarily inhabit the harsh, treeless expanses of the tundra biome. Belonging to the subfamily Arvicolinae (which includes voles and muskrats), the lemming is a foundational species in its ecosystem, acting as a primary food source for many Arctic predators.
Physical Traits and Natural Habitat
Lemmings typically measure between four and seven inches in length and possess a stocky, rounded body shape. Their dense, insulating fur allows them to remain active year-round without hibernation. This fur often changes color seasonally; for example, the collared lemming develops a white coat for winter camouflage.
They have short appendages—tiny ears, a stubby tail, and short legs—which are adaptations that minimize heat loss in the frigid climate. The front feet feature a specialized, flattened claw used for digging through hard-packed snow and frozen soil. They use these claws to create complex tunnel systems beneath the snowpack, where they forage and make nests out of grasses and mosses.
The lemming’s diet is strictly herbivorous, consisting mainly of mosses, grasses, and sedges during warmer months. In the winter, they rely on roots, berries, and lichens accessed through their subnivean tunnels. Their geographic range stretches across the Arctic Circle, including Scandinavia, Siberia, Alaska, and Northern Canada.
Rapid Life Cycles and Population Booms
The lemming’s life history is characterized by an incredibly rapid breeding cycle. These rodents can reach sexual maturity in a matter of weeks, sometimes as early as 14 days old. Females have a short gestation period of approximately three weeks and can produce multiple litters per year, often breeding beneath the snow during the Arctic winter.
This high reproductive capacity leads to cyclical population surges, often called “boom-and-bust” cycles, which occur roughly every three to five years. During a peak year, lemming numbers can increase a hundredfold or more, quickly straining the local food supply and available habitat. The resulting resource depletion forces large numbers of the animals to disperse outward to search for new, less crowded territories.
This mass dispersal is a biological response to overpopulation and an ecological necessity to relieve pressure on the environment. The movement is often directional, driven by instinct to find new feeding grounds. This push for new territory is a survival strategy.
Debunking the Mass Suicide Myth
The popular image of lemmings intentionally marching over a cliff to commit mass suicide is entirely fictional. This misconception stems from a misinterpretation of their dispersal behavior. When lemmings encounter a body of water, such as a river or wide lake, they will attempt to swim across it while searching for resources.
Lemmings are capable swimmers, but their small size and limited endurance mean they can easily drown if the water is too wide or turbulent. Furthermore, the animals have poor eyesight, and when migrating in large numbers, they may accidentally fall off a steep bank or cliff face. These accidental drownings or falls are the basis for the myth of intentional self-destruction.
The myth was cemented in the public consciousness by the 1958 Walt Disney nature film White Wilderness. An investigation revealed that the film’s climactic sequence of lemmings plunging into the ocean was entirely staged. The filmmakers transported the animals to an unnatural location and then deliberately herded and pushed them off a cliff to create the dramatic footage.