Lemming

Lemmings
Lemmus lemmus
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, in tundra biomes. They are subniveal animals, and together with 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 rats, mice, hamsters, and gerbils.

Description and habitat

Lemmings weigh from 30 to 112 g (1.1 to 4.0 oz) and are about 7 to 15 cm (2.8 to 5.9 in) long. They generally have long, soft fur, and very short tails. They are herbivorous, feeding mostly on leaves and shoots, grasses, and sedges in particular, but also on roots and bulbs. At times, they will eat grubs and larva. Like other rodents, their incisors grow continuously, allowing them to exist on much tougher forage than would normally be possible.

Lemmings do not hibernate through the harsh northern winter. They remain active, finding food by burrowing through the snow and utilizing grasses clipped and stored in advance. 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 when food is plentiful.

Behavior

The behavior 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 Norway lemming and Brown lemming are two of the few vertebrates who reproduce so quickly that their population fluctuations are chaotic,^[1][2] rather than following linear growth to a carrying capacity or regular oscillations. It is unknown why lemming populations fluctuate with such variance roughly every four years, before plummeting to near extinction.^[3] Lemming behavior and appearance is markedly different from many other rodents, who are inconspicuously colored and try to conceal themselves from their predators. Lemmings, on the contrary, are conspicuously colored, and behave aggressively towards predators and even human observers. It has been suggested that lemming defense system is based on aposematism (warning display)^[4]

While for many years it was believed that the population of lemmings changed with the population cycle, there is now some evidence to suggest that the predators' populations, particularly the stoat may be more closely involved in changing the lemming population.^[5]

Misconceptions

Misconceptions about lemmings go back many centuries. In the 1530s, the geographer Zeigler of Strasbourg proposed the theory that the creatures fell out of the sky during stormy weather (also featured in the folklore of the Inupiat/Yupik at Norton Sound), and then died suddenly when the grass grew in spring.^[6] This description was contradicted by the natural historian Ole Worm, who accepted that the lemmings could fall out of the sky but claimed that they had been brought over by the wind rather than created by spontaneous generation. It was Worm who first published dissections of a lemming, which showed that they are anatomically similar to most other rodents, and the work of Carl Linnaeus proved that the animals had a natural origin.^[7][8]

When large numbers of lemmings get on the move, some of them will inevitably drown while crossing rivers and lakes, like this one in Norway.

Lemmings became the subject of a popular misconception that they commit mass suicide when they migrate. Actually, it is not a mass suicide but the result of their migratory behavior. Driven by strong biological urges, some species of lemmings may migrate in large groups when population density becomes too great. Lemmings can swim and may choose to cross a body of water in search of a new habitat. In such cases, many may drown if the body of water is so wide as to stretch their physical capability to the limit. This fact combined with the unexplained fluctuations in the population of Norwegian lemmings gave rise to the misconception.^[9]

The misconception of lemming "mass suicide" is long-standing and has been popularized by a number of factors. In 1955, Disney Studio illustrator Carl Barks drew an Uncle Scrooge adventure comic with the title "The Lemming with the Locket". This comic, which was inspired by a 1954 American Mercury article, showed massive numbers of lemmings jumping over Norwegian cliffs.^[10][11] Even more influential was the 1958 Disney film White Wilderness, which won an Academy Award for Documentary Feature, in which staged footage was shown with lemmings jumping into certain death after faked scenes of mass migration.^[12] A Canadian Broadcasting Corporation documentary, Cruel Camera, found that the lemmings used for White Wilderness were flown from Hudson Bay to Calgary, Alberta, Canada, where they did not jump off the cliff, but were in fact launched off the cliff using a turntable.^[13]

This same act was also used in the Apple Computer 1985 Super Bowl commercial "Lemmings" and the popular 1991 video game Lemmings, in which the player must stop the lemmings from mindlessly marching over cliffs or into traps. In a 2010 board game by GMT games, "Leaping Lemmings," players must maneuver lemmings across a board while avoiding hazards and successfully launch them off a cliff.

Because of their association with this odd behavior, lemming suicide is a frequently used metaphor in reference to people who go along unquestioningly with popular opinion, with potentially dangerous or fatal consequences. This metaphor is seen many times in popular culture, such as in the video game Lemmings, and in episodes of Red Dwarf and Adult Swim's show Robot Chicken. In the ninth episode of season 1 of Showtime's The Borgias, the Pope's second son Juan refers to the college of cardinals as lemmings when they flee the Vatican in anticipation of an impending French invasion. The Blink 182 song "Lemmings" also uses this metaphor as does the 1973 stage show National Lampoon's Lemmings starring John Belushi and mocking post-Woodstock groupthink.^[14]

Classification

• Order Rodentia
  • Superfamily Muroidea
    • Family Cricetidae
      • Subfamily Arvicolinae: voles, lemmings, and related species
        • Tribe Lemmini
          • Dicrostonyx
            • St. Lawrence Island Collared Lemming (Dicrostonyx exsul)
            • Northern Collared Lemming (Dicrostonyx groenlandicus) or
            • Ungava Collared Lemming (Dicrostonyx hudsonius)
            • Victoria Collared Lemming (Dicrostonyx kilangmiutak)
            • Nelson's Collared Lemming (Dicrostonyx nelsoni)
            • Ogilvie Mountains 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)
            • Siberian Brown Lemming (Lemmus sibiricus)
            • North American Brown Lemming (Lemmus trimucronatus)
            • Wrangel Island Lemming (Lemmus portenkoi)
          • Myopus
            • Wood Lemming (Myopus schisticolor)
          • Synaptomys
            • Northern Bog Lemming (Synaptomys borealis)
            • Southern Bog Lemming (Synaptomys cooperi)
        • Tribe Arvicolini: over 120 species
          • Eolagurus
            • Yellow Steppe Lemming (Eolagurus luteus)
            • Przewalski's Steppe Lemming (Eolagurus przewalskii)
          • Lagurus
            • Steppe Lemming (Lagurus lagurus)
          • Over 100 other species not known as lemmings

References

External links

Look up lemming in Wiktionary, the free dictionary.

• The Lemming CyclePDF (92.6 KiB) article by Nils Christian Stenseth on the population cycles of lemmings and other northern rodents.
  • See also The Lemming Cycle, in HTML format.
• Collared LemmingPDF (177 KiB) Article about Collared Lemming, see also the main page on Alaskan mammals
• Rebuttal of lemming suicide:
  • Alaska Wildlife News.
  • Lemmings, dying on camera.