One of the undoubted highlights of my first trip to arctic Norway was this Norway Lemming. We couldn’t believe our eyes when we saw this fantastic creature scurrying across the tundra towards us!
Animal Diversity Web states that the Norway lemmings are active during the day as well as the night. They spend their waking periods (6 hours on average) foraging and moving about. As a species of the northern latitudes, they can be exposed to up to 24 hours of daylight in the summer, so having active periods during the day and night is most likely an adaptive response to their environment. Norway lemmings prefer to live independently of each other, and they can become aggressive toward each other during periods of overcrowding. Male lemmings are known to engage in boxing, wrestling, and threatening behaviour. Their independent nature may be one of the driving factors in dispersal during their population peaks. During these peaks the lemming population will disperse beyond their normal range in search of more space and more food. They may even move into the taiga and forests which are not their preferred habitat. This great abundance of lemmings can decimate the heath shrubs, mosses and lichens which they most commonly feed upon. Generally, the population peaks occur every 3 to 5 years. However, some studies have found that the number of years between the peaks have been increasing and peaks are less regular in occurrence. This irregularity is attributed to climate change. With shorter winters, there is less snow cover and lemmings rely on the snow cover during the winter to provide safe access to food and shelter while breeding and raising their young. (Haim, et al., 2004; Henttonen, 2012; Jordan, 2004; Macdonald, 1984; Moen, et al., 1993)