Dicrostonyx Lemmus Synaptomys Myopus  * Incomplete listing: see vole
Lemmings are small rodents, usually found in or near the Arctic, in tundra biomes. 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.
A group of lemmings is referred to as a "revolution", e.g. "a revolution of lemmings".

Lemmings weigh from 30 to 112 grams (1–4 oz) and are about 7 to 15 centimetres (2.75 – 6 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. 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. They remain active, finding food by burrowing through the snow and utilising 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 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).

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.
Lemmings of northern Norway are one of the few vertebrates who reproduce so quickly that their population fluctuations are chaotic,
Due to their association with this odd behaviour, 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 is the theme of the video game Lemmings, where the player attempts to save the mindlessly marching rodents from walking to their deaths.



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)
              Siberian Brown Lemming (Lemmus sibiricus)
              North American Brown Lemming (Lemmus trimucronatus)
              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
                        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 http://aknhp.uaa.alaska.edu/zoology/Zoology_ADFG_mammals.htm
                          Rebuttal of lemming suicide:
                          
                          
                          
                          • Alaska Wildlife News.
                            Snopes (Urban Legends Reference Pages) entry on Disney's White Wilderness.
                            Lemmings, dying on camera.