The Arctic lemming is a small rodent native to the vast, treeless expanse of the tundra across the Northern Hemisphere. Various species exist, including the Brown Lemming (Lemmus trimucronatus) and the Collared Lemming (Dicrostonyx groenlandicus). These animals are active year-round, surviving in one of the planet’s most challenging environments. Their survival depends on their specialized diet and ability to locate food beneath the snowpack. The lemming’s feeding habits are a driving force in the Arctic ecosystem, directly influencing the population cycles of predators like the Arctic fox and snowy owl.
Primary Food Sources
Arctic lemmings are strict herbivores, relying exclusively on the vegetation that grows in the cold tundra. Their diet is composed primarily of graminoids (grasses and sedges), along with mosses and lichens. Sedges are often a preferred food item during the brief summer season when their shoots are tender and nutrient-dense.
Dietary preferences vary significantly between the main lemming genera. Brown Lemmings (Lemmus) prefer graminoids and moss, common in moist, low-lying habitats. Conversely, Collared Lemmings (Dicrostonyx) select shrubs like willow and various herbs, often found in drier, more elevated tundra areas. Mosses remain an important fallback food source when more palatable vegetation is scarce.
Adapting to Seasonal Changes
The lemming diet shifts to cope with the differences between the short Arctic summer and the long winter. During the continuous daylight of summer, lemmings feed on the most nutritious parts of plants, including flowering shoots, berries, and tender green leaves. This period allows them to build up fat reserves for the cold season. Their selective feeding maximizes the intake of energy and macronutrients during the limited growing period.
Throughout the winter, lemmings remain active beneath the thick, insulating layer of snow, known as the subnivean space; they do not hibernate. Their winter diet consists of tougher, less digestible materials accessed under the snow or cached earlier. This includes the bark and twigs of dwarf shrubs like willow and birch, along with frozen plant material, roots, and bulbs. Consuming these fibrous materials helps maintain the energy required to stay warm and active.
Foraging and Feeding Behavior
Lemmings spend up to six hours daily consuming food to sustain their high metabolism. Their small bodies and specialized feeding apparatus are adapted for foraging in the tundra. They possess continually growing incisors and robust claws, used to gnaw through tough plant material and dig through frozen soil or snow.
In winter, foraging involves creating extensive tunnel systems within the subnivean space, allowing them to access ground-level vegetation while remaining hidden from predators. They follow established routes between nests and feeding patches, efficiently harvesting roots and basal parts of plants. Their digestive tract is highly efficient at processing the low-quality, fibrous plant matter common in the Arctic, which is necessary for surviving on a challenging food supply.