Lemming

? Lemmings
A lemming
Scientific classification
Kingdom: Animalia Phylum: Chordata Class: Mammalia Order: Rodentia Family: Cricetidae Subfamily: Arvicolinae Tribe: Lemmini*
Genera
Dicrostonyx Lemmus Synaptomys Myopus * Incomplete listing: see vole

Lemmings are small rodents, usually found in or near the Arctic. Together with the voles and muskrats, they make up the subfamily Arvicolinae (also known as Microtinae), which forms part of the largest mammal radiation by far, the superfamily Muroidea, which also includes the rats, mice, hamsters, and gerbils.

Lemmings mostly weigh between 30 g and 112 g (1 to 4 oz) and are about 7 cm - 15 cm (2.75 to 6 in) long. They usually have long, soft fur and very short tails. They are herbivorous, feeding mostly on leaves and shoots, grasses, and sedges in particular, but also roots and bulbs in some cases. Like many rodents, their incisors grow continuously, allowing them to exist on much tougher forage than would otherwise be possible.

Lemmings do not hibernate through the harsh northern winter, but remain active, finding food by burrowing through the snow, and utilising grasses clipped and stored in anticipation. They are solitary animals by nature, meeting only to mate and then going their separate ways, but like all rodents they have a high reproductive rate and can breed rapidly in good seasons.

There is little to distinguish a lemming from a vole. Most lemmings are members of the tribe Lemmini (one of the three tribes that make up the subfamily)

Population fluctuations

Lemming populations go through rapid growths and subsequent crashes that have achieved an almost legendary status, largely because of the well-known Disney Studios film, White Wilderness, which was produced in 1958 and reappeared on television at regular intervals for many years afterwards. White Wilderness popularized, using staged footage, the myth that during population booms Norway Lemmings become suicidal and leap en masse off cliffs into the sea. For this reason, the term "lemming" is often used in slang to denote those who mindlessly follow the crowd, even if destruction is the result.

In fact, the behaviour of lemmings is much the same as that of many other rodents which have periodic population booms and then disperse in all directions, seeking the food and shelter that their natural habitat cannot provide. (The Australian Long-haired Rat is one example.)

Myths about lemmings go back many centuries, and in the 16th and 17th centuries there was much speculation in learned circles that lemmings were in fact spontaneously generated by conditions of the air. This was argued against, successfully, by the natural historian Ole Worm, who provided one of the first published dissections of a lemming. In his investigation, Worm showed that a lemming contained anatomy similar to most other rodents, including testes.

The populations of predatory creatures like foxes and owls follow the population changes of lemmings and voles.

Classification

• ORDER RODENTIA
  • Superfamily Muroidea
    • Family Cricetidae
      • Subfamily Arvicolinae
        • Tribe Lemmini
          • Dicrostonyx
            • St Lawrence Island Collared Lemming (Dicrostonyx exsul)
            • Northern Collared Lemming (Dicrostonyx groenlandicus)
            • Ungava Collared Lemming (Dicrostonyx hudsonius)
            • Victoria Collared Lemming (Dicrostonyx kilangmiutak)
            • Nelson's Collared Lemming (Dicrostonyx nelsoni)
            • Ogilvie Mountain Collared Lemming (Dicrostonyx nunatakensis)
            • Richardson's Collared Lemming (Dicrostonyx richardsoni)
            • Bering Collared Lemming (Dicrostonyx rubricatus)
            • Arctic Lemming (Dicrostonyx torquatus)
            • Unalaska Collared Lemming (Dicrostonyx unalascensis)
            • Wrangel Lemming (Dicrostonyx vinogradovi)
          • Lemmus
            • Amur Lemming (Lemmus amurensis)
            • Norway Lemming (Lemmus lemmus)
            • Brown Lemming (Lemmus sibiricus)
          • Myopus
            • Wood Lemming (Myopus schisticolor)
          • Synaptomys
            • Northern Bog Lemming (Synaptomys borealis)
            • Southern Bog Lemming (Synaptomys cooperi)
        • Tribe Ellobiini: mole voles, 5 species
        • Tribe Microtini: voles, 121 species
          • Eolagurus
            • Yellow Steppe Lemming (Eolagurus luteus)
            • Przewalski's Steppe Lemming (Eolagurus przewalskii)
          • Lagurus
            • Steppe Lemming (Lagurus lagurus)
          • 118 other species known as voles or muskrats