The lemming breeds on treeless mountain areas in Finland, Sweden, Norway and the Kola Peninsula. It feeds on various species of moss, shoots and grass, sedges and rush. In winter it prefers places with good snowdrifts. In the summer it searches to damp areas by mountain brooks and other waterways even further down on the mountain. In the fall it climbs back to treeless mountain tops. The lemmings are known for migrating in droves. They can be seen running across the roads and highways outside their natural habitat. The periodic population booms cause them to disperse in all directions, seeking the food and shelter their natural habitats cannot provide. However, population booms are getting ever rarer due to climate change.
The lemming is a protected species by law.
ADAPTING TO THE WINTER
The lemming has adapted well to the winter; it may even reproduce in the winter season, if there is enough snow. On treeless mountain tops the snow gathers to heaps and drifts of up to three metres. The lemmings are well sheltered from the harshest cold. The lemming does not store food for the winter; it is active through the winter, eating fresh moss tops under the snow. The incisors grow longer in the winter, allowing them to forage effectively on the hard ground under the snow.
CLASS: Mammalia - mammals
ORDER: Rodentia - rodents
SIZE: Weight: 10-110g, length: 70-155mm + length of tail 10-19mm.
BREEDING: Heat: year round, 2-4 litters per year. Incubation period: 21 days and nights, offspring in a litter: 5-7. Sexual maturity reached in 5 weeks.
LIFESPAN: 2 years at the most.