More Information

Mustela ermineaermine

By Heather Loso

Ge­o­graphic Range

Er­mine have a cir­cum­po­lar dis­tri­b­u­tion. They are found in the north tem­per­ate re­gions of Eura­sia and North Amer­ica. In the New World, they range from east to west in a broad belt from the Arc­tic Ocean and ad­ja­cent is­lands of the Cana­dian Arch­i­pel­ago south­ward into the north­ern United States. Er­mine are ab­sent from the Great Plains. (Ruff and Wil­son, 1999)

Habi­tat

Er­mine pre­fer ri­par­ian wood­lands, marshes, shrubby fencerows, and open areas ad­ja­cent to forests or shrub bor­ders. Al­though er­mine are pri­mar­ily ter­res­trial, they climb trees and swim well. Tree roots, hol­low logs, stone walls, and ro­dent bur­rows are used as dens. Dens are usu­ally around 300 mm below ground. Er­mine line their nests with dry veg­e­ta­tion, and fur and feath­ers from prey. Side cav­i­ties of bur­rows are used as food caches and la­trines. (Ruff and Wil­son, 1999)

Phys­i­cal De­scrip­tion

At full adult size total body length from head to rump is 170 mm to 330 mm. Males are gen­er­ally twice as large as fe­males, with males weigh­ing from 67 to 116 grams and fe­males from 25 to 80 grams. The tail length is about 35% of the total body length, rang­ing from 42 mm to 120 mm. Er­mine have the typ­i­cal weasel form: long body, short legs, long neck sup­port­ing a tri­an­gu­lar head, slightly pro­trud­ing round ears, bright black eyes, and long whiskers. Their short, mod­er­ately fine fur is white in the win­ter and the tip of the tail is black. In the sum­mer, the dor­sal fur is choco­late brown while the ven­tral fur ex­tend­ing to the upper lip is yel­low­ish white.

  • Sexual Dimorphism
  • male larger
  • Range mass
    25 to 116 g
    0.88 to 4.09 oz
  • Range length
    170 to 330 mm
    6.69 to 12.99 in
  • Average basal metabolic rate
    1.276 W
    AnAge

Re­pro­duc­tion

Er­mine are a polyg­y­nous-promis­cu­ous species, with males and fe­males mat­ing op­por­tunis­ti­cally.

Er­mine mate in late spring to early sum­mer. Fe­males are polye­strous, but pro­duce only 1 lit­ter per year. Young are born in April or May after an av­er­age ges­ta­tion pe­riod of 280 days, which in­cludes an 8 to 9 month pe­riod of de­vel­op­men­tal delay. Longer days be­gin­ning in March trig­ger the re­sump­tion of fetal de­vel­op­ment. Lit­ter size ranges from 3 to 18 off­spring and av­er­ages 4 to 9. The sex ratio is un­equal. Young are blind and help­less. They are cov­ered with fine white hair, and a promi­nent dark mane of dense fur de­vel­ops around the neck by the third week (func­tion un­known). The young grow quickly and are able to hunt with their mother by their eighth week. Al­though fe­males do not reach adult size until a least 6 weeks after birth, they are able to mate when they are 60 to 70 days old, often be­fore they are weaned. Males do not breed or gain adult di­men­sions until their sec­ond sum­mer.

Fe­males in na­ture may sur­vive for at least 2 breed­ing sea­sons, while males gen­er­ally do not sur­vive this long. Re­pro­duc­tive suc­cess is highly de­pen­dent on food avail­abil­ity.

  • Breeding interval
    Ermine generally breed once yearly.
  • Breeding season
    Ermine mate in late spring to early summer.
  • Range number of offspring
    3 to 18
  • Average number of offspring
    4-9
  • Average number of offspring
    6.77
    AnAge
  • Average gestation period
    280 days
  • Average gestation period
    43 days
    AnAge
  • Average weaning age
    8-10 weeks
  • Average age at sexual or reproductive maturity (female)
    60-70 days
  • Average age at sexual or reproductive maturity (female)
    Sex: female
    95 days
    AnAge
  • Average age at sexual or reproductive maturity (male)
    2 years
  • Average age at sexual or reproductive maturity (male)
    Sex: male
    365 days
    AnAge

Fe­males ex­clu­sively care for their off­spring, nurs­ing and pro­tect­ing them until they be­come in­de­pen­dent. The young are born blind and help­less.

  • Parental Investment
  • no parental involvement
  • altricial
  • pre-fertilization
    • provisioning
    • protecting
      • female
  • pre-hatching/birth
    • provisioning
      • female
    • protecting
      • female
  • pre-weaning/fledging
    • provisioning
      • female
    • protecting
      • female
  • pre-independence
    • provisioning
      • female
    • protecting
      • female

Lifes­pan/Longevity

The av­er­age life span of an er­mine is 1 to 2 years; the max­i­mum is 7 years. (Ruff and Wil­son, 1999)

  • Range lifespan
    Status: wild
    7 (high) years
  • Typical lifespan
    Status: wild
    1 to 2 years
  • Average lifespan
    Status: wild
    1-2 years
  • Range lifespan
    Status: captivity
    12.5 (high) years
    AnAge

Be­hav­ior

The er­mine's lithe, agile body al­lows it to move swiftly both above ground and through un­der­ground bur­rows. Fe­males hunt in tun­nels more than males, which may ex­plain the higher num­ber of males that are trapped. Er­mine can also run eas­ily across snow. This ideal preda­tor hunts in a zigzag pat­tern, pro­gress­ing by a se­ries of leaps of up to 50 cm each. Er­mine in­ves­ti­gate every hole and crevice, often stop­ping to sur­vey their sur­round­ings by rais­ing their heads and stand­ing up­right on their hindlegs. They may travel up to 15 km in one night.

Adult males dom­i­nate fe­males and young. Fe­males tend to re­main in their birth place through­out their lives. Males dis­perse and at­tain large ter­ri­to­ries that usu­ally en­com­pass or over­lap fe­males' ter­ri­to­ries.

Male and fe­male er­mine only as­so­ci­ate with one an­other dur­ing the breed­ing sea­son. (Ruff and Wil­son, 1999)

  • Range territory size
    0.1 to 0.2 km^2

Home Range

Er­mine pop­u­la­tion den­si­ties fluc­tu­ate with prey abun­dance. When con­di­tions are good, an in­di­vid­ual may oc­cupy a 10ha area. The max­i­mum home range size is about 20ha. Home ranges of males are usu­ally twice the size of fe­male home ranges. These soli­tary mam­mals main­tain ex­clu­sive bound­aries that are pa­trolled and marked by scent. (Ruff and Wil­son, 1999)

Com­mu­ni­ca­tion and Per­cep­tion

Er­mine have keen senses of smell, vi­sion, hear­ing, and touch that help them to lo­cate prey. Most mustelids are fairly quiet an­i­mals, but some vo­cal­iza­tions may be used in in­tra-spe­cific com­mu­ni­ca­tion. Chem­i­cal cues are prob­a­bly the main means of com­mu­ni­cat­ing re­pro­duc­tive readi­ness to po­ten­tial mates.

Food Habits

Er­mine are car­ni­vores that hunt pri­mar­ily at night. They are spe­cial­ist preda­tors on small, warm-blooded ver­te­brates, prefer­ably mam­mals of rab­bit size and smaller. When mam­malian prey is scarce, er­mine eat birds, eggs, frogs, fish, and in­sects. In se­vere cli­mates, er­mine fre­quently hunt under snow and sur­vive en­tirely on small ro­dents and lem­mings. Daily meals are es­sen­tial to meet the er­mine's ex­hor­bi­tant en­ergy and heat pro­duc­tion de­mands. Er­mine cache left­over meals as a way of deal­ing with these de­mands. (Ruff and Wil­son, 1999)

Once a po­ten­tial prey is iden­ti­fied, the er­mine ap­proaches as closely as pos­si­ble. With in­cred­i­ble speed it grasps the back of the vic­tim's head and neck with sharp teeth, and wraps its body and feet around the vic­tim. The vic­tim dies from re­peated bites to the base of the skull. Er­mine have keen senses that help them lo­cate prey. Hares and ro­dents are mainly fol­lowed by scent, in­sects by sound, and fish by sight. (Ruff and Wil­son, 1999)

  • Primary Diet
  • carnivore
    • eats terrestrial vertebrates
  • Animal Foods
  • birds
  • mammals
  • amphibians
  • fish
  • eggs
  • insects

Pre­da­tion

Er­mine are fierce and ag­gres­sive, al­though diminu­tive, an­i­mals. Po­ten­tial preda­tors are larger car­ni­vores in­clud­ing red fox, gray fox, martens, fish­ers, bad­gers, rap­tors, and oc­ca­sion­ally do­mes­tic cats.

Ecosys­tem Roles

Er­mine are im­por­tant preda­tors on small mam­mal com­mu­ni­ties in the ecosys­tems in which they live.

Many er­mine die from a par­a­sitic ne­ma­tode (Skr­jabingy­lus na­si­cola) that in­fects the nasal pas­sage, dis­tort­ing the si­nuses. Even­tu­ally the skull is per­fo­rated and pres­sure is ex­erted on the brain, caus­ing death. Shrews are be­lieved to be the car­rier hosts of this par­a­site. (Ruff and Wil­son, 1999)

Com­men­sal/Par­a­sitic Species
  • ne­ma­tode worms

Eco­nomic Im­por­tance for Hu­mans: Pos­i­tive

Hu­mans trap thou­sands of er­mine each sea­son, but the de­mand for pelts has re­cently de­creased. The white win­ter fur has long been used in trim­ming coats and mak­ing stoles. Er­mine are ex­cel­lent mousers, which makes them valu­able to hu­mans.

  • Positive Impacts
  • body parts are source of valuable material
  • controls pest population

Eco­nomic Im­por­tance for Hu­mans: Neg­a­tive

Er­mine, and other Mustela species can take do­mes­tic fowl when they can gain ac­cess to them.

Con­ser­va­tion Sta­tus

Er­mine are not con­sid­ered threat­ened or en­dan­gered, al­though hunt­ing pres­sure in some areas may im­pact pop­u­la­tions se­verely. (Ruff and Wil­son, 1999)

Other Com­ments

There are 16 Palearc­tic and 10 Nearc­tic sub­species rec­og­nized.

Con­trib­u­tors

Al­li­son Poor (ed­i­tor), Uni­ver­sity of Michi­gan-Ann Arbor.

Heather Loso (au­thor), Uni­ver­sity of Michi­gan-Ann Arbor.

Glossary

Nearctic

living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.

World Map

Palearctic

living in the northern part of the Old World. In otherwords, Europe and Asia and northern Africa.

World Map

acoustic

uses sound to communicate

altricial

young are born in a relatively underdeveloped state; they are unable to feed or care for themselves or locomote independently for a period of time after birth/hatching. In birds, naked and helpless after hatching.

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

carnivore

an animal that mainly eats meat

chemical

uses smells or other chemicals to communicate

crepuscular

active at dawn and dusk

delayed implantation

in mammals, a condition in which a fertilized egg reaches the uterus but delays its implantation in the uterine lining, sometimes for several months.

embryonic diapause

At about the time a female gives birth (e.g. in most kangaroo species), she also becomes receptive and mates. Embryos produced at this mating develop only as far as a hollow ball of cells (the blastocyst) and then become quiescent, entering a state of suspended animation or embryonic diapause. The hormonal signal (prolactin) which blocks further development of the blastocyst is produced in response to the sucking stimulus from the young in the pouch. When sucking decreases as the young begins to eat other food and to leave the pouch, or if the young is lost from the pouch, the quiescent blastocyst resumes development, the embryo is born, and the cycle begins again. (Macdonald 1984)

endothermic

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

fertilization

union of egg and spermatozoan

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

holarctic

a distribution that more or less circles the Arctic, so occurring in both the Nearctic and Palearctic biogeographic regions.

World Map

Found in northern North America and northern Europe or Asia.

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

motile

having the capacity to move from one place to another.

mountains

This terrestrial biome includes summits of high mountains, either without vegetation or covered by low, tundra-like vegetation.

native range

the area in which the animal is naturally found, the region in which it is endemic.

nocturnal

active during the night

polygynandrous

the kind of polygamy in which a female pairs with several males, each of which also pairs with several different females.

riparian

Referring to something living or located adjacent to a waterbody (usually, but not always, a river or stream).

scent marks

communicates by producing scents from special gland(s) and placing them on a surface whether others can smell or taste them

scrub forest

scrub forests develop in areas that experience dry seasons.

seasonal breeding

breeding is confined to a particular season

sedentary

remains in the same area

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

solitary

lives alone

stores or caches food

places a food item in a special place to be eaten later. Also called "hoarding"

tactile

uses touch to communicate

taiga

Coniferous or boreal forest, located in a band across northern North America, Europe, and Asia. This terrestrial biome also occurs at high elevations. Long, cold winters and short, wet summers. Few species of trees are present; these are primarily conifers that grow in dense stands with little undergrowth. Some deciduous trees also may be present.

temperate

that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).

terrestrial

Living on the ground.

territorial

defends an area within the home range, occupied by a single animals or group of animals of the same species and held through overt defense, display, or advertisement

tropical savanna and grassland

A terrestrial biome. Savannas are grasslands with scattered individual trees that do not form a closed canopy. Extensive savannas are found in parts of subtropical and tropical Africa and South America, and in Australia.

savanna

A grassland with scattered trees or scattered clumps of trees, a type of community intermediate between grassland and forest. See also Tropical savanna and grassland biome.

temperate grassland

A terrestrial biome found in temperate latitudes (>23.5° N or S latitude). Vegetation is made up mostly of grasses, the height and species diversity of which depend largely on the amount of moisture available. Fire and grazing are important in the long-term maintenance of grasslands.

tundra

A terrestrial biome with low, shrubby or mat-like vegetation found at extremely high latitudes or elevations, near the limit of plant growth. Soils usually subject to permafrost. Plant diversity is typically low and the growing season is short.

visual

uses sight to communicate

viviparous

reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.

Ref­er­ences

Baker, Rollin H. 1983. Michi­gan Mam­mals, pg.472-478. Michi­gan State Uni­veristy

Press, Michi­gan.

Edger, Ju­dith L. 1990. Pat­terns of ge­o­graphic vari­a­tion in the skull of Nearc­tic Er­mine (Mustela er­minea). Cana­dian Jour­nal of Zo­ol­ogy, 68:1241-1248. Na­tional Re­search

Coun­cil of Canada, On­tario.

Jones, J. Knox and Elmer C. Bir­ney. 1988. Hand­book of Mam­mals of the North-Cen­tral States, pg. 254. Uni­ver­sity of Min­nesota Press, Min­nesota.

King, Car­olyn M. 1983. Mam­malian Species,195:1-8. The Amer­i­can So­ci­ety of Mam­mal­o­gists, New York.

Kurta, Allen. 1995. Mam­mals of the Great Lakes, pg. 228-231. Uni­ver­sity of Michi­gan Press, Michi­gan.

Nowak, Ronald M. and J.L. Par­adiso. 1983. Walker's Mam­mals of the World, 2:988-989.

The John Hop­kins Uni­ver­sity Press, Bal­ti­more and Lon­don.

"An­i­mal Life His­to­ries Data­base" (On-line).

Ruff, S., D. Wil­son. 1999. The Smith­son­ian Book of North Amer­i­can Mam­mals. Wash­ing­ton [D.C.]: Smith­son­ian In­sti­tu­tion Press in as­so­ci­a­tion with the Amer­i­can So­ci­ety of Mam­mal­o­gists.

Search

Navigation Links

Information
Pictures
Specimens
Classification

Classification

  • Kingdom Animalia animals
  • Phylum Chordata chordates
  • Subphylum Vertebrata vertebrates
  • Class Mammalia mammals
  • Order Carnivora carnivores
  • Family Mustelidae badgers, otters, weasels, and relatives
  • Genus Mustela ermines, ferrets, minks, and weasels
  • Species Mustela erminea ermine