Animal Diversity Web

Ge­o­graphic Range

Nor­way lem­mings are dis­trib­uted across Fennoscan­dia, a re­gion stretch­ing from the Russ­ian Kola Penin­sula to the west coast of Nor­way and from the north­ern coast of Nor­way south to the Baltic Sea. How­ever, Lem­mus lem­mus may mi­grate fur­ther south if the species goes through a pop­u­la­tion boom. (Haim, et al., 2004; Hamel, et al., 2013; Hent­to­nen, 2012)

• Biogeographic Regions
• palearctic
  • native

• Other Geographic Terms
• holarctic

Habi­tat

Nor­way lem­mings are found in tun­dra and alpine re­gions. Dur­ing the win­ter they live in in­su­lated spaces under the snow. This pro­vides them with warmth, shel­ter, ac­cess to food, and pro­tec­tion from preda­tors. Hav­ing this shel­ter gives young lem­mings a bet­ter chance of sur­vival. In times with­out snow cover, Nor­way lem­mings may live in a va­ri­ety of bogs, marshes, and other moist ter­res­trial habi­tats. They also in­habit heath­land where dwarf shrubs are the main veg­e­ta­tion. Nor­way lem­mings find safety by dig­ging shal­low bur­rows or by oc­cu­py­ing al­ready formed spaces un­der­ground. (Hamel, et al., 2013; Hent­to­nen, 2012; Kaus­rud, et al., 2008; Mac­don­ald, 1984; Ravolainen, et al., 2011)

• Habitat Regions
• temperate
• polar
• terrestrial

• Terrestrial Biomes
• tundra

• Wetlands
• marsh
• swamp
• bog

Phys­i­cal De­scrip­tion

Nor­way lem­mings weigh be­tween 20 and 130 g. Body length ranges from 8 to 17.5 cm. They have thick bod­ies with heavy coats for main­tain­ing body heat against the cold. Fur color is black and brown with some golden-yel­low streaks. The un­der­belly is a lighter color than the rest of their fur. Nor­way lem­mings re­tain the same fur color, re­gard­less of sea­son, and the males and fe­males are gen­er­ally sim­i­lar in size and color. They do not have a con­spic­u­ous tail. Their teeth are char­ac­ter­is­tic of their sub­fam­ily, Mi­croti­nae: 12 mo­lars, 4 in­cisors, and flat­tened crowns. Their limbs are short and mostly tucked under the body. The claw of the first digit on each paw is larger and flat­ter than the rest of the claws. This mod­i­fi­ca­tion helps lem­mings to tun­nel through snow. Their basal meta­bolic rate is 1.0710 W. (Jor­dan, 2004; Mac­don­ald, 1984; Nowak, 1999; Tacutu, et al., 2013)

• Other Physical Features
• endothermic
• homoiothermic
• bilateral symmetry

• Sexual Dimorphism
• sexes alike

• Range mass

  20 to 130 g

  0.70 to 4.58 oz

• Range length

  8 to 17.5 cm

  3.15 to 6.89 in

• Average basal metabolic rate

  1.0710 cm3.O2/g/hr

• Average basal metabolic rate

  1.071 W

  AnAge

Re­pro­duc­tion

Nor­way lem­mings breed year round. Al­though they gen­er­ally live in­de­pen­dently of each other, they will en­counter one an­other briefly for mat­ing. Lem­mings may be­come ag­gres­sive to­ward one an­other when there are too many other lem­mings in close prox­im­ity, and male Nor­way lem­mings have been ob­served en­gag­ing in box­ing and wrestling be­hav­ior. In other species of lem­mings, box­ing and ag­gres­sion are parts of the mat­ing sys­tem, so it may be that this oc­curs in Nor­way lem­mings as well. No in­for­ma­tion was found in the sci­en­tific lit­er­a­ture in­di­cat­ing whether Nor­way lem­mings are monog­a­mous or polyg­y­nous or polyg­y­nan­drous; how­ever, con­sid­er­ing char­ac­ter­is­tics of other lem­mings and the in­de­pen­dent na­ture of Nor­way lem­mings, they are not likely to be monog­a­mous. Fe­males of the genus Lem­mus un­dergo post-par­tum es­trous, so a fe­male may be re­cep­tive to mat­ing shortly after giv­ing birth to a lit­ter. (Jor­dan, 2004; Mac­don­ald, 1984; Nowak, 1999)

• Mating System
• polygynous
• polygynandrous (promiscuous)

Nor­way lem­mings are able to re­pro­duce rapidly and they breed year round. On av­er­age, sex­ual ma­tu­rity is reached at 3 weeks for fe­males (al­though a 2 week old preg­nant fe­male has been recorded) and at one month for males. They can pro­duce a lit­ter every 3 to 4 weeks with a ges­ta­tion pe­riod of 16 days. Mem­bers of the genus Lem­mus may have ges­ta­tion pe­ri­ods last­ing be­tween 16 and 23 days. Each lit­ter of Nor­way lem­mings yield be­tween 5 and 13 young. Time to wean­ing for this genus is usu­ally 14 to 16 days, and the birth weight of Lem­mus young is 3.3 grams. Mem­bers of this genus also ex­pe­ri­ence post-par­tum es­trous, so the fe­male may be preg­nant with her next lit­ter while still car­ing for the young from her pre­vi­ous lit­ter. (Jor­dan, 2004; Kaus­rud, et al., 2008; Mac­don­ald, 1984; Nowak, 1999)

• Key Reproductive Features
• iteroparous
• year-round breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual
• viviparous
• post-partum estrous

• Breeding interval

  Norway lemmings can produce a litter every 3 to 4 weeks.

• Breeding season

  Norway lemmings will breed year-round.

• Range number of offspring

  5 to 13

• Average number of offspring

  7

  AnAge

• Average gestation period

  16 days

• Average gestation period

  19 days

  AnAge

• Range age at sexual or reproductive maturity (female)

  2 to 4 weeks

• Average age at sexual or reproductive maturity (male)

  4 weeks

• Average age at sexual or reproductive maturity (male)
  Sex: male

  44 days

  AnAge

No in­for­ma­tion is cur­rently avail­able on parental in­vest­ment in Nor­way lem­mings. Gen­er­ally, how­ever, vole and lem­ming fe­males are the care­givers and males do not play a role in care giv­ing, ex­cept in a few monog­a­mous species. Fe­males in sub­fam­ily Mi­croti­nae are usu­ally very pro­tec­tive of their young and will keep their off­spring close to them. Fe­males in the genus Lem­mus wean their young in 14 to 16 days. (Mac­don­ald, 1984; Nowak, 1999)

• Parental Investment
• female parental care
• pre-hatching/birth
  • provisioning
    • female
  • protecting
    • female
• pre-weaning/fledging
  • provisioning
    • female
  • protecting
    • female

Lifes­pan/Longevity

The old­est recorded Nor­way lem­ming was a spec­i­men in cap­tiv­ity which lived for 3.3 years. Lem­mus species gen­er­ally live for 1 to 2 years. (Nowak, 1999)

• Range lifespan
  Status: captivity

  3.3 (high) years

• Average lifespan
  Status: captivity

  2.0 years

  Max Planck Institute for Demographic Research

Be­hav­ior

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 be­hav­ior. 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)

• Key Behaviors
• terricolous
• diurnal
• nocturnal
• motile
• sedentary
• territorial

Home Range

When pop­u­la­tions are low there may be 3 to 50 Nor­way lem­mings per ha (1.2 to 20 lem­mings per acre), and when the pop­u­la­tion is high there may be up to 330 lem­mings per ha (134 lem­mings per acre). (Mac­don­ald, 1984)

Com­mu­ni­ca­tion and Per­cep­tion

No in­for­ma­tion is cur­rently avail­able specif­i­cally on com­mu­ni­ca­tion and per­cep­tion in Nor­way lem­mings. Voles and lem­mings have well-de­vel­oped senses, such as smell and hear­ing. Some species of lem­mings use scents to mark bound­aries, and many species of lem­mings can rec­og­nize mem­bers of their own species by their scents. Voles and lem­mings use dif­fer­ent calls for dis­tress, ag­gres­sion, and mat­ing. Each species has a unique set of calls. (Mac­don­ald, 1984)

• Communication Channels
• tactile
• acoustic
• chemical

• Other Communication Modes
• scent marks

• Perception Channels
• visual
• tactile
• acoustic
• chemical

Food Habits

Nor­way lem­mings are her­biv­o­rous. They mainly eat mosses, lichens, bark, and some grasses. Mosses thrive when there has been a suf­fi­cient amount of snow over the win­ter. Food may be dif­fi­cult or dan­ger­ous to ob­tain just be­fore win­ter when there are rains and freez­ing tem­per­a­tures with­out snow cover. (Jor­dan, 2004; Mac­don­ald, 1984; Nowak, 1999)

• Primary Diet
• herbivore
  • folivore
  • lignivore

• Plant Foods
• leaves
• wood, bark, or stems
• seeds, grains, and nuts
• bryophytes
• lichens

Pre­da­tion

The pop­u­la­tion den­si­ties of Fennoscan­dian preda­tors are shown to be tied to the pop­u­la­tion cy­cles of Nor­way lem­mings and other small ro­dents with cyclic pop­u­la­tion changes. Com­mon preda­tors of Nor­way lem­mings in­clude red foxes, Arc­tic foxes, er­mines, weasels, snowy owls, ravens, and other birds of prey. Fall is a par­tic­u­larly op­por­tune time for lem­ming preda­tors be­cause there is no snow cover and plant food sources are scarce due to freez­ing tem­per­a­tures. With less avail­able food, lem­mings may stray fur­ther away from their bur­rows than usual and leave them­selves vul­ner­a­ble to pre­da­tion. Their bur­rows, whether in the ground or under the snow, are a lem­ming's main de­fense against preda­tors. Aer­ial preda­tors and larger preda­tors have a more dif­fi­cult time ac­cess­ing the bur­rows. Preda­tors such as er­mines and weasels may be able to find their way into the lem­mings' bur­rows. (Hamel, et al., 2013; Mac­don­ald, 1984)

• Anti-predator Adaptations
• cryptic

• Known Predators

  • Arctic foxes (Vulpes lagopus)
  • red foxes (Vulpes vulpes)
  • snowy owls (Nyctea scandiaca)
  • common ravens (Corvus corax)
  • ermine (Mustela erminea)

Ecosys­tem Roles

Dur­ing pop­u­la­tion peaks, when there are up to 134 lem­mings per acre, the dam­age that Nor­way lem­mings in­flict on veg­e­ta­tion can take the area up to four years to re­cover from. While the ef­fect to the tun­dra land­scape can be neg­a­tive dur­ing these times, the ef­fect on preda­tor pop­u­la­tions can be pos­i­tive. For ex­am­ple, Arc­tic foxes (Vulpes lago­pus) have a higher prob­a­bil­ity of re­col­o­niz­ing an area when lem­mings are abun­dant and when their com­peti­tor,red foxes (Vulpes vulpes), do not live in the area. Nor­way lem­mings are hunted by both of these foxes, and Arc­tic foxes spe­cial­ize in hunt­ing lem­mings specif­i­cally. It has been sug­gested that hav­ing more in­for­ma­tion on Nor­way lem­ming pop­u­la­tions could help un­der­stand how to sup­port threat­ened Arc­tic fox pop­u­la­tions. (Hamel, et al., 2013; Kaus­rud, et al., 2008; Mac­don­ald, 1984)

• Ecosystem Impact
• disperses seeds

Eco­nomic Im­por­tance for Hu­mans: Pos­i­tive

Nor­way lem­mings have been use­ful in stud­ies of pop­u­la­tion cy­cling. Their pop­u­la­tion cy­cles were first noted in myths and leg­ends as the Scan­di­na­vian peo­ple de­scribed hordes of lem­mings march­ing across the land every 3 to 5 years. A Swedish Catholic priest named Olaus Mag­nus was the first to il­lus­trate Nor­way lem­ming mi­gra­tions in 1555 in his His­to­ria de gen­tibus septen­tion­al­ibus ("His­tory of the North­ern Peo­ples"). The wood­cut shows hor­rific giant ro­dents de­scend­ing from the skies (es­sen­tially ap­pear­ing out of nowhere) and at­tack­ing smaller crea­tures. While this is an ex­treme ex­ag­ger­a­tion, it cap­tures the spirit of fas­ci­na­tion and cu­rios­ity which led to these an­i­mals being so well-stud­ied in their pop­u­la­tion cy­cles. The cy­cles of lem­mings and their rel­a­tives are the foun­da­tion for a lot of re­search in pop­u­la­tion dy­nam­ics, veg­e­ta­tion growth, and as an ex­am­ple of the ef­fects of cli­mate change. (Hamel, et al., 2013; Kaus­rud, et al., 2008; Mac­don­ald, 1984; Ravolainen, et al., 2011)

• Positive Impacts
• research and education

Eco­nomic Im­por­tance for Hu­mans: Neg­a­tive

De­spite the leg­ends, Nor­way lem­mings have lit­tle to no neg­a­tive im­pact on human agri­cul­ture or eco­nom­ics. Al­though the lem­mings may mi­grate into more pop­u­lated areas dur­ing years of high pop­u­la­tion den­sity, they mainly live out of the way of human agri­cul­tural areas. (Mac­don­ald, 1984)

Con­ser­va­tion Sta­tus

The IUCN states that the pop­u­la­tions of Nor­way lem­mings are sta­ble and of least con­cern for en­dan­ger­ment. Pos­si­ble fu­ture threats in­clude cli­mate change and graz­ing of other her­bi­vores which re­duces lem­ming habi­tat. Over­all, Nor­way lem­mings are a rather suc­cess­ful species in the area where they live. (Hent­to­nen, 2012)

• IUCN Red List

  Least Concern
  More information

• IUCN Red List

  Least Concern
  More information

• US Federal List

  No special status

• CITES

  No special status

• State of Michigan List

  No special status

Other Com­ments

Dur­ing pop­u­la­tion peaks, Nor­way lem­mings ex­hibit large scale dis­per­sal. While many other ro­dents ex­pe­ri­ence pop­u­la­tion peaks, Nor­way lem­mings are the only species that will em­bark on long dis­tance mi­gra­tions. Their mi­gra­tions have be­come fa­mous through leg­ends and sto­ries. One com­mon mis­con­cep­tion is that lem­mings set out on these mi­gra­tions with the in­tent to drown them­selves in the sea. Al­though mass drown­ing of lem­mings do occur on these mi­gra­tions (it is the num­ber one cause of death on the jour­ney), lem­mings are not sui­ci­dal. In nor­mal con­di­tions, lem­mings are ac­tu­ally able to swim fairly well; how­ever, the sheer num­ber of lem­mings and the im­pend­ing ob­sta­cle be­fore them seems to trig­ger a panic ef­fect in the crea­tures caus­ing them to drown dur­ing the cross­ing. This phe­nom­e­non is an­other rea­son why lem­ming pop­u­la­tion cy­cles are so well stud­ied. (Hent­to­nen, 2012; Jor­dan, 2004; Mac­don­ald, 1984; Nowak, 1999)

Con­trib­u­tors

Alexan­dria Stub­ble­field (au­thor), Sierra Col­lege, Jen­nifer Skillen (ed­i­tor), Sierra Col­lege, Tanya Dewey (ed­i­tor), Uni­ver­sity of Michi­gan-Ann Arbor.

Ref­er­ences

Haim, A., S. Saarela, E. Ho­htola, N. Zis­apel. 2004. Daily rhythms of oxy­gen con­sump­tion, body tem­per­a­ture, ac­tiv­ity and mela­tonin in the Nor­we­gian lem­ming Lem­mus lem­mus under north­ern sum­mer pho­tope­riod. Jour­nal of Ther­mal Bi­ol­ogy, 29 (7-8): 629-633. Ac­cessed March 06, 2013 at http://​www.​sciencedirect.​com/​science/​article/​pii/​S030645650400110X.

Hamel, S., S. Kil­len­green, J. Hen­den, N. Yoc­coz, R. Ims. 2013. Dis­en­tan­gling the im­por­tance of in­ter­spe­cific com­pe­ti­tion, food avail­abil­ity, and habi­tat in species oc­cu­pancy: Re­col­o­niza­tion of the en­dan­gered Fennoscan­dian arc­tic fox. Bi­o­log­i­cal Con­ser­va­tion, 160: 114-120. Ac­cessed March 06, 2013 at http://​www.​sciencedirect.​com/​science/​article/​pii/​S0006320713000219.

Hent­to­nen, H. 2012. "IUCN Red List of Threat­ened Species. Ver­sion 2012.2" (On-line). Ac­cessed April 06, 2013 at http://​www.​iucnredlist.​org/​.

Jor­dan, M. 2004. Rats, Mice, and Rel­a­tives I: Voles and Lem­mings (Ar­vi­col­i­nae). Pp. 225-238 in M Hutchins, A Evans, J Jack­son, D Kleiman, J Mur­phy, D Thoney, eds. Grz­imek's An­i­mal Life En­cy­clo­pe­dia, Vol. 16: Mam­mals V., 2nd Edi­tion. De­troit: Gale. Ac­cessed April 01, 2013 at http://​go.​galegroup.​com/​ps/​i.​do?​id=GALE%7CCX3406700978&​v=2.​1&​u=rock89639&​it=r&​p=GVRL&​sw=w.

Kaus­rud, K., A. Mys­terud, H. Steen, J. Vik, E. Østbye, B. Cazelles, E. Fram­stad, A. Eike­set, I. Mys­terud, T. Solhøy, N. Stenseth. 2008. Link­ing cli­mate change to lem­ming cy­cles. Na­ture, 456(7218): 93-97. Ac­cessed March 17, 2013 at http://​www.​nature.​com/​nature/​journal/​v456/​n7218/​full/​nature07442.​html.

Mac­don­ald, D. 1984. The En­cy­clo­pe­dia of Mam­mals. New York: Facts on File, Inc..

Moen, J., P. Lund­berg, L. Ok­sa­nen. 1993. Lem­ming graz­ing on snowbed veg­e­ta­tion dur­ing a pop­u­la­tion peak, North­ern Nor­way. Arc­tic and Alpine Re­search, 25(2): 130-135. Ac­cessed April 29, 2013 at http://​www.​jstor.​org/​stable/​1551549.

Nowak, R. 1999. True Lem­mings. Pp. 1481-1482 in Walker's Mam­mals of the World, Vol. 2, 6th Edi­tion. Bal­ti­more and Lon­don: The John Hop­kins Uni­ver­sity Press.

Ravolainen, V., K. Bråthen, R. Ims, N. Yoc­coz, J. Hen­den, S. Kil­len­green. 2011. Rapid, land­scape scale re­sponses in ri­par­ian tun­dra veg­e­ta­tion to ex­clu­sion of small and large mam­malian her­bi­vores. Basic and Ap­plied Ecol­ogy, 12(8): 643-653. Ac­cessed March 06, 2013 at http://​www.​sciencedirect.​com/​science/​article/​pii/​S1439179111001228.

Tacutu, R., T. Craig, A. Bu­dovsky, D. Wut­tke, G. Lehmann, D. Taranukha, J. Costa, V. Fraifeld, J. de Ma­g­a­l­hes. 2013. "AnAge: The An­i­mal Age­ing and Longevity Data­base" (On-line). Human Ge­nomic Re­sources: In­te­grated data­bases and tools for the bi­ol­ogy and ge­net­ics of age­ing. Ac­cessed May 04, 2013 at http://​genomics.​senescence.​info/​species/​entry.​php?​species=Lemmus_​lemmus.