![]() ![]() The lemming population in any given area varies wildly, increasing up to tenfold in some years. This fast breeding and fast death means that at peak times, up to 30% of the lemming population can die off every two weeks! They also have a relatively short natural lifespan, usually only one or two years 3. These 'incredible numbers' of lemmings are a dietary staple for many Arctic predators like foxes, weasels, owls, wolves, wolverines, hawks, gulls, and falcons. – The Voyage of the Vega round Asia and Europe, Adolf Erik Nordenskiöld 2, 1881 ![]() The ground besides is at certain places so thickly strewed with lemming dung, that it must have a considerable influence on the condition of the soil. During the snow-melting season these passages form channels for running off the water, small indeed, but everywhere to be met with, and contributing in a considerable degree to the drying of the ground. Thousands and thousands of animals must be required in order to carry out this work even over a small area. For at the commencement of summer, when the snow has recently melted away, there are to be seen, everywhere in the level fertile places in the very close grass of the meadows, footpaths about an inch and a half deep, which have been formed during winter by the trampling of these small animals, under the snow, in the bed of grass or lichens which lies immediately above the frozen ground. The gestation period is well under a month, and the young are sexually mature shortly after they start walking, at about two weeks! The lemming is not found on Spitzbergen, but must at certain seasons occur in incredible numbers on Novaya Zemlya. During this time the females are nearly continually pregnant, usually bearing two to three litters with a general average of seven (but up to 13) young per litter. Lemmings generally only come together to mate - and mate they do! Determined (or bored) animals can start as early as January, but the height of the breeding season is generally during the warmer summer months from June through September. They are also creatures of habit, travelling the same routes every day (or night - they seem to have no set bedtimes) between their favourite food sources and their burrows, until they make recognisable paths and extensive systems of burrows and tunnels. Unlike many rodents, lemmings are solitary creatures. In times when food is scarce and competition strong, they have been known to turn cannibalistic, eating their own young or weaker members of their species. Lemmings don't hibernate, but stay awake and alive all winter at temperatures as low as −25☌, burrowing deep under the snow 1 for warmth, and eating bark and twigs to stay alive. ![]() These teeth allow them to forage on roots and bulbs, along with their preferred diet of softer plant parts like shoots, grasses, and berries. Like all rodents, they have incisors that grow continually. To conserve warmth they have thick fur and very short tails, with ears that can be folded close to their heads. They are usually mottled brown or grey with paler underbellies, though the collared lemming (genus Dicrostonyx) is the only rodent whose fur turns white in the winter. There are variations in size between species, but they generally range from 7-14cm in length (without tail) and weigh between 30g and 115g. Lemmings closely resemble voles and are often difficult to distinguish from them, or from one another. While the 'true lemmings' of the genus Lemmus live in the tundras of the far North, in or near the Arctic circle, those of other genera are found as far afield as the deserts of China and Mongolia. Lemmings are rodents from the family Cricetidae, the second-largest family of mammals, which includes other rodents such as hamsters and voles as well as most of the wild rats and mice found in the Americas. ![]()
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