Least Weasel (Mustela nivalis)

Least weasel (Mustela nivalis) by Snowmanradio

Scientific name: Mustela nivalis

Common name: Least weasel

Phylum: Chordata

Class: Mammalia

Order: Carnivora

Family: Mustelidae

Other common names: Weasel, العرسة البيتى, ling-you, yin-shu, 伶鼬, 白鼠, 银鼠, 伶鼬, 白鼠, 银鼠, wezel, lumikko, belette d'Europe, belette pygmée, kleines weisel, kleinweisel, mausweisel, zwergweisel, donnola, mostèla, Ласка

Measurements: This is the smallest species of the order Carnivora.  Weight 30-250 g, head-body length 11.4-26 cm, tail length 7-9 cm.  Males are 10-20% longer than females and weigh 50-100% more than females.

Description: Long and skinny with short legs.  Brown on top, white to yellow (often with spots) underneath during summer.  Winter colouration in colder climes changes to all white, but remains the same as summer colouration in warmer areas. For a mustelid, the tail is proportionally short.

Native range: Afghanistan, Albania, Andorra, Armenia, Austria, Azerbaijan, Belarus, Belgium, Bosnia & Herzegovina, Bulgaria, Canada, China, Croatia, Czech Republic, Denmark, Estonia, Finland, France, Georgia, Germany, Greece, Hungary, Iran, Italy, Japan, Kazakhstan, Kyrgyzstan, Latvia, Lebanon, Liechtenstein, Lithuania, Luxembourg, Macedonia, Moldova, Monaco, Mongolia, Montenegro, Netherlands, North Korea, Norway, Poland, Portugal, Romania, Russian Federation, San Marino, Serbia, Slovakia, Slovenia, Spain, South Korea, Sweden, Switzerland, Syria, Taiwan, Tajikistan, Turkey, Turkmenistan, Ukraine, United Kingdom, United States, and Uzbekistan

Introduced to: New Zealand, Malta, Crete, The Azores, and Sao Tomé

Habitat: Found in many habitats: open forests, fields, prairies, scrub, semi-deserts, and even coastal dunes. They are not found in dense forest or sandy deserts.

IUCN conservation status: Least concern

Movements: There are no seasonal movements.  Young animals can disperse large distances in the search for a territory.

Diet: Primarily eats small rodents, but when those are scarce will eat young lagomorphs (like rabbits), birds and their eggs & nestlings, insects, small reptiles, amphibians, fish, and larger rodents.

Social organisation: Least weasels are solitary apart from breeding and are very territorial.

Voice/sounds: They make hisses, chirps, squeaks, squeals, and trills; listen to them here: 1 2 3

Breeding behaviour: Females give birth to young in dens and raise them without the help of the male.  Least weasels appear to be promiscuous.

Breeding season: May happen throughout the year but is primarily in spring through summer.

Number of offspring: 1-12 (usually 4-7)

Gestation period: 34-37 days

Growth of young: They weigh 1.1-1.7 g at birth and are blind, deaf, and naked.  Eyes and ears open during their 4^th week, weaning starts at about a month old and is completed 1^1/2-3^1/2 weeks later when they are 50-60 g, the young leave by 9-12 weeks old, and they are sexually mature at 3 months.

General behaviour: They will have several dens which they take from their prey (they do not dig their own).  They will often cache excess food either in a side tunnel of their den or somewhere near where the prey was killed.  This species is so small that it can chase most of its prey down into their own burrows.

This video, while overly dramatic, shows a least weasel (Mustela nivalis) in action, as well as giving you an idea of their small size. The least weasel part of the video starts at 26 minutes and 35 seconds in.

References:

Deanesly, R.  (1944).  The reproductive cycle of the female weasel (Mustela nivalis).  Proceedings of the Zoological Society of London, 114, 339-349.

East, K., & Lockie, J.D.  (1965).  Further observations on weasels (Mustela nivalis) and stoats (Mustela erminea) born in captivity.  Proceedings of the Zoological Society of London, 147, 234-238.

Erlinge, S.  (1974).  Distribution, territoriality and numbers of the weasel Mustela nivalis in relation to prey abundance.  Oikos, 25, 308-314.

Erlinge, S.  (1975).  Feeding habits of the weasel Mustela nivalis in relation to prey abundance.  Oikos, 26, 378-384.

Encyclopedia of Life.  (2018).  http://www.eol.org.

Gillingham, B.J.  (1984).  Meal size and feeding rate in the least weasel (Mustela nivalis).  Journal of Mammalogy, 65, 517-519.

Hayssen, V., van Tienhoven, A., & van Tienhoven, A.  (1993).  Asdell's patterns of mammalian reproduction: A compendium of species-specific data.  Ithaca: Comstock Publishing Associates.

Heidt, G.A.  (1972).  Anatomical and behavioral aspects of killing and feeding by the least weasel, Mustela nivalis L.  Journal of the Arkansas Academy of Science, 26, 53-54.

Heidt, G.A., & Huff, J.N.  (1970).  Ontogeny of vocalization in the least weasel.  Journal of Mammalogy, 51, 385-386.

Heidt, G.A., Petersen, M.K., & Kirkland, G.L., Jr.  (1968).  Mating behavior and development of least weasels (Mustela nivalis) in captivity.  Journal of Mammalogy, 49, 413-419.

Hill, M.  (1939).  The reproductive cycle of the male weasel (Mustela nivalis).  Proceedings of the Zoological Society of London, 109, 481-512.

Huff, J.N., & Price, E.O.  (1968).  Vocalizations of the least weasel, Mustela nivalis.  Journal of Mammalogy, 49, 548-550.

International Union for Conservation of Nature.  The IUCN Red List for endangered species. (2018).  http://iucnredlist.org.

King, C.M.  (1975).  The home range of the weasel (Mustela nivalis) in an English woodland.  Journal of Animal Ecology, 44, 639-668.

King, C.M.  (1980).  The weasel Mustela nivalis and its prey in an English woodland.  Journal of Animal Ecology, 49, 127-159.

King, C.M.  (1980).  Population biology of the weasel Mustela nivalis on British game estates.  Holarctic Ecology, 3, 160-168.

King, C.M.  (2017).  The history of transportations of stoats (Mustela erminea) and weasels (M. nivalis) to New Zealand, 1883-92.  International Review of Environmental History, 3, 51-87.

King, C.M.  (2017).  Liberation and spread of stoats (Mustela erminea) and weasels (M. nivalis) in New Zealand, 1883-1920.  New Zealand Journal of Ecology, 41, 163-177.

Moors, P.J.  (1975).  The food of weasels (Mustela nivalis) on farmland in north-east Scotland.  Journal of Zoology, 177, 455-461.

Moors, P.J.  (1977).  Studies of the metabolism, food consumption and assimilation efficiency of a small carnivore, the weasel (Mustela nivalis L.).  Oecologia, 27, 185-202.

Polder, E.  (1968).  Spotted skunk and weasel populations den and cover usage by northeast Iowa.  Proceedings of the Iowa Academy of Science, 75, 142-146.

Rodrigues, M, Bos, A.R., Schembri, P.J., Lima, R.F. de, Lymberakis, P., Parpal, L., Cento, M., Ruette, S., Ozkurt, S.O., Santos-Reis, M., Merilä, M., & Fernandes, C.  (2017).  Origin and introduction history of the least weasel (Mustela nivalis) on Mediterranean and Atlantic islands inferred from genetic data.  Biological Invasions, 19, 399-421.

Sheffield, S.R., & King, C.M.  (1994).  Mustela nivalis.  Mammalian Species, 454, 1-10.

Strang, K., Castro, I., Blunden, G., & Shepherd, L.  (2017).  The diet of weasels (Mustela nivalis vulgaris) from Purerua Peninsula, Bay of Islands, New Zealand.  New Zealand Journal of Zoology, 45, 83-90.

Tapper, S.  (1979).  The effect of fluctuating vole numbers (Microtis agrestis) on a population of weasels (Mustela nivalis) on farmland.  Journal of Animal Ecology, 48, 603-617.

Wilson, D.E., & Mittermeier, R.A. editors.  (2009).  Handbook of the mammals of the world. Volume 1: Carnivores.  Barcelona: Lynx Edicions.