Dicrostonyx – Collared lemmings

Found across tundra landscapes in North America, Greenland, and parts of Siberia, these small animals may look unassuming at first glance, but they are uniquely adapted to survive in some of the coldest, harshest environments on Earth. They get their common name from the light-colored “collar” or pale band of fur that some species show around their neck and shoulders, though their most dramatic transformation is their seasonal coat. Unlike most small mammals, collared lemmings are the only lemmings that turn completely white in winter, giving them camouflage against snow. In summer, their fur is brownish or gray, blending with tundra plants and soil, showing how finely tuned they are to a landscape that shifts drastically with the seasons.

Their role at the heart of the Arctic food web makes collared lemmings so ecologically important. Their populations follow a boom-and-bust cycle, surging every three to five years before crashing, then building up again. When lemming numbers are high, predators like snowy owls, Arctic foxes, weasels, and even wolves thrive, raising more offspring thanks to the abundant prey. When numbers decline, predators must turn to other animals, often with ripple effects across the ecosystem.

Collared lemmings also have fascinating behavioral and physical adaptations. They are active year-round, never hibernating, and during the long, dark Arctic winters, they live beneath the snow in a network of tunnels. The snow acts as a natural blanket, keeping temperatures in their burrows much warmer than the freezing air above. They dig special chambers for food storage and nesting, and they feed mostly on grasses, mosses, sedges, and twigs. A quirky trait is that their front claws actually grow longer and more curved in winter, functioning almost like shovels for digging through ice-crusted snow.