The lemming is a small, stout rodent of the Arctic, known for its dramatic and often misunderstood behavior. These creatures inhabit the vast tundra regions of the Northern Hemisphere, often remaining hidden beneath the snow or dense vegetation. Rumors of mass disappearances fuel questions about their survival. This article explores the current state of lemming populations and clarifies the reality behind these widespread myths.
Current Status of Lemmings
Lemmings are not extinct and continue to thrive across the circumpolar Arctic and sub-Arctic tundra. They are widespread throughout northern Canada, Alaska, Scandinavia, and Russia. Several distinct species exist, including the Norway lemming (Lemmus lemmus), the Siberian brown lemming (Lemmus sibiricus), and the collared lemming (Dicrostonyx groenlandicus).
These short-tailed, thickset rodents are adapted to their environment, remaining active year-round without hibernating. They inhabit remote, treeless areas where they dig extensive burrow systems into the soil and under the snowpack. Although their populations undergo massive, periodic fluctuations, the species is resilient and continues to fulfill its ecological role.
Lemmings in the Arctic Ecosystem
The lemming is a primary consumer, feeding mostly on grasses, sedges, and mosses. This makes it a major regulator of vegetation composition on the tundra. Their feeding habits influence the growth cycle of plants and affect soil nutrient dynamics through their burrowing and droppings. As one of the few small rodent species in the high Arctic, they have a disproportionate influence on the food web.
The most characteristic feature of lemming populations is their boom-and-bust cycle, which typically peaks every three to five years. During a population boom, lemming density can reach high levels, altering the landscape through intense grazing. These fluctuations directly dictate the survival and reproductive success of numerous predators in the ecosystem.
Predators such as the Arctic fox, snowy owl, ermine, and weasel rely heavily on lemmings as a main food source. In years of lemming abundance, these predators experience a surge in breeding success and population numbers. When the lemming population crashes, predators struggle to find food, leading to population declines or forcing them to switch to alternative prey like ptarmigans and hares. The stability of the tundra food web is linked to the lemming cycle.
Debunking the Myths of Mass Disappearance
The belief that lemmings vanish or commit mass suicide is a cultural misconception with no basis in scientific fact. The myth was popularized by the 1958 Disney documentary White Wilderness, which staged a scene of lemmings supposedly throwing themselves into the ocean. Investigations later confirmed the filmmakers had purchased lemmings and herded them over a cliff to create the false footage.
The reality behind the myth is the animals’ natural dispersal behavior following a population explosion. When lemming numbers become too high and resources become scarce, large groups migrate across the landscape in search of new habitat. This is a survival mechanism driven by competition for food and territory.
During these large-scale movements, the rodents may encounter obstacles like rivers or lakes, which they attempt to cross. Many individuals drown during these crossings or fall victim to predators, leading to mass mortality events. These accidental deaths were misinterpreted and sensationalized as intentional acts of collective suicide.
Real Threats to Lemming Survival
Lemmings face genuine and increasing threats stemming from environmental change. The most significant modern challenge is the rapid warming of the Arctic climate, which disrupts their crucial winter habitat. Throughout the winter months, lemmings live and breed within the subnivean layer, an insulated, protective space between the ground and the snowpack.
Warmer winters are increasingly characterized by “rain-on-snow” events, where precipitation falls as rain or where snow melts and refreezes. This creates a dense, impenetrable layer of ice within the snowpack that seals off the subnivean space. The icy barrier prevents lemmings from accessing the vegetation they need for food and eliminates their insulated shelter.
The destruction of the subnivean layer leads to widespread mortality, causing population crashes and disrupting the regular lemming cycle. This change in winter conditions is a primary factor behind the observed decline and irregularity of lemming populations in parts of Fennoscandia and Greenland. The breakdown of this cycle poses a threat to the lemmings and the specialized predators that depend on them.