A lemming isn't just a character in a video game or a random term for someone who blindly follows the crowd. This is a small animal, similar to a vole, that has earned an undeserved reputation as a mindless drone that would follow another off a cliff. Lemmings move together in large numbers in the same direction, but do so in search of food, not to jump off ledges together.
Size and Appearance
Lemmings are rodents and are typically about the size of a mouse, measuring between four and 5.5 inches long and weighing about one ounce. They look more like a miniature guinea pig than a mouse, however, with round faces, tubby bodies and short tales. In the summer, lemmings sport brown coats, but in the winter they turn white to help them blend in with the snow to avoid predators. They have extremely thick furs to protect them against harsh winter weather.
Lemmings live mainly in the Arctic and cool northern climates. They make their home in the tundra, building complex underground tunnel systems and burrows that shelter them from heat during the summer. In the winter they create shallow tunnels and burrows under the snow, mainly to keep them hidden from predators. They use moss and grass to build nests inside snowy tunnels to stay comfortable and warm. Their range includes nearly all of the Arctic Circle, including Alaska, Canada, Scandinavia and Siberia.
Breeding takes place mainly during warmer months, between May and August, and the female gives birth only three weeks after mating. The average litter size can vary greatly between two and 13, but averages seven to eight. Females become fertile again immediately after giving birth, and their young are sexually mature at only five to six weeks old, with some becoming fertile at a tender three weeks old during summer months.
Lemmings spend about six hours every day searching for food. They are herbivores, eating bulbs, roots, sprouts and just about any vegetation they can find in the harsh tundra. They have small sharp teeth, similar to mice, so they can shear through tough plant matter easily. The lemming population fluctuates regularly depending on the amount of food available. In times of scarcity the population shrinks, but in times of abundance it increases.