WEASEL SPECIES OF ASIA AND EUROPE

SIBERIAN WEASELS

Siberian weasel

Siberian weasels(Mustela sibirica) are also known as kolonok. They are medium-sized weasels native to eastern Asia, mainly in Russia and China, where they are widely distributed in a variety of habitats. Siberian weasels are be found as far north to the Sea of Okhotsk area and the Russian Far East and as far south as Hong Kong, Taiwan and Guangdong Province of China. Further west they are found as far south as Tibet and the Gobi Desert, and as far west as European Russia. Their lifespan is generally less than three years. Ones have lived up to 8.8 years in captivity.

Siberian weasels are found in secondary forests, primary forest, coniferous plantations, tundra, mountains and agricultural. Itachi in Japan were thought to be a subspecies of Siberian weasels but a study of their mitochondral DNA indicate they are two distinct species. This same study revealed that a population of Siberian weasels introduced to Japan from Korea may be going through a genetic bottleneck. Studies in Taiwan suggest they prefer living at elevations from 1,400 to 1,700 meters on ridges with 13 degree slopes to areas near water with slopes up to 37 degrees.[Source: Jason Kreutzer, Animal Diversity Web (ADW) |=|]

On the International Union for Conservation of Nature (IUCN) Red List Siberian weasels are listed as a species of Least Concern. As predators, these weasels play a role in controlling small rodent population bu they also viewd as pests for raiding chiclen coops. Studies have shown that anal-gland secretions of Siberian weasels cause rice-field rats to go into self-destrpying, self-anointing behavior. As a result, Siberian weasels have been being introduced into agricultural areas to help control populations of these rats.

Siberian Weasel Characteristics and Diet

Siberian weasels range in weight from 360 to 820 grams (12.7 to 28.9 ounces) and have a head and body length that ranges from 25 to 39 centimeters (9.84 to 15.35 inches). Their tail is about half the length of their body. Foot length measures from six to 7.2 centimeters (2.4 to 2.8 inches). Sexual Dimorphism (differences between males and females) is present: Males are larger than females. Males have a head and body length of 28 to 39 centimeters (11 to 15.35 inches), with 15.5-to-21 centimeter (6 to 8 inch) tail, and weigh from 650 to 820 grams. (22.9 to 28.9 ounces) Females have a head and body length of 25 to 30.5 centimeters (9.84 to 12 inches) with a 13.3-to-16.4 (5.3-to-6.4 inch) centimeter tail and weigh 360 to 430 grams (12.7 to 51.1 ounces). [Source: Jason Kreutzer, Animal Diversity Web (ADW) |=|]

range of Siberian weasel range; red is where they have been introduced

Like most weasels, Siberian weasels have a long, stretched out body with relatively short legs. Their head is elongated, narrow and relatively small, and its short ears are broad at the base. are pale brown on the back, gradually changing to a paler, yellowish brown below. The tip of the tail may be a darker shade of brown than the rest, but is not black. Their winter fur is very dense, soft and fluffy, with guard hairs reaching 3–4 centimeters (1.2–1.6 inches) in length.

Siberian weasels are primarily carnivores (eat meat or animal parts) and mostly eat small mammals, birds, eggs, insects, and non-insect arthropods such as spiders, eggs, insects and non-insect arthropods. Like other mustelids, Siberian weasels are efficient and fierce predators. In the coastal areas of southern China they feed on rice-field rats. In the Nakdong Estuary of South Korea, they feed on little terns and their eggs. In the subtropical forests of Taiwan they eat a variety of small mammals, including shrews, rats and mice and switch to beetles, grubs, other insects and other invertebrates) when small mammal populations are low. They store and cache food, especially in preparation for winter when food runs low. They have been known to make mass migrations when there are food shortages.

Siberian Weasel Behavior and Reproduction

Siberian weasels are terricolous (live on the ground), crepuscular (active at dawn and dusk). nocturnal (active at night), motile (move around as opposed to being stationary), sedentary (remain in the same area), territorial (defend an area within the home range). They sense using touch and chemicals usually detected with smell. [Source: Jason Kreutzer, Animal Diversity Web (ADW) |=|] |=|

With the exception of the association between mothers and their young and brief encounters by males and females to mate,Siberian weasels are solitary. They maintain territories, although they are known to migrate in times of food shortages. They have been observed moving up to eight kilometers in a single night. Like other weasels they are capable of putting up a good fight against attackers larger than themselves. The primary predators of weasels are large raptors, such as owls and hawks.

range of yellow-bellied weasels

Siberian weasels are polygynous (males have more than one female as a mate at one time) and engage in seasonal breeding. The breeding season is from May to June. Males may fight over access to females during this time. The gestation period ranges from 28 to 30 days. The number of offspring ranges from two to 12, with the average number of offspring being five or six.

Several males may court a single female, and fights between males have been observed. Parental care is provided by females in a nest for several months. Births occur from April to June. Young are altricial, meaning they are relatively underdeveloped at birth. They open their eyes at one month of age. The average weaning age is 56 days. Young disperse from their mother's range in the fall. On average males and females reach sexual or reproductive maturity at two years.

Yellow-Bellied Weasels

Yellow-bellied weasels (Mustela kathiah) are a species of weasel that inhabit pine forests in central and eastern Asia. They are named for their yellow-colored underbelly. Their backside and tail are dark brown. They have a head a and body length of 25 to 27 centimeters (9.8–10.6 inches), with a 12–15 centimeter (4.9–5.9 inch) tail that is about half as long as their body. Their mean weight is about 1.5 kilograms (3.3 pounds). The upper lip, chin and throat are a lighter yellow-white color. The foot pads are well developed and exposed. The soles of the hind feet are naked. On the International Union for Conservation of Nature (IUCN) Red List they are classified as a species of “Least Concern”. [Source: Wikipedia, Kerstin Bandner, Animal Diversity Web (ADW) |=|]

Yellow-bellied weasels is found from northern Pakistan to southeast China, and throughout southeast Asia. They are sometimes found above timber line and reside in forests and mountains at elevations from 1,800 to 4,000 meters (5,900 to 13,125 feet). They mainly eat rodents such as mice, rats, and voles. They will also eat birds and small mammals. Weasels are known for their ferocity, hunting skills and aggression. Yellow-bellied weasels has been referred to as a hyperactive bundle of concentrated predatory energy. It is likely that yellow-bellied weasels play a role in controlling rodent populations in the areas where they live. |=|

yellow-bellied weasel

Yellow-bellied weasels are solitary, nocturnal (active at night), motile (move around as opposed to being stationary) and territorial (defend an area within the home range). They are easily tamed and can be used to control rodents within human structures. Nepalese keep them to get rid of rodents in their homes and have trained them to attack larger animals such as geese, goats, and sheep for sport. Yellow-bellied weasels sense using touch and chemicals usually detected with smell. Their excellent sight, hearing, and sense of smell allows them to easily track their prey. With their lean build, they are able to chase rats and mice in their burrows and kill them with a bite to the neck.

Yellow-bellied weasels employ delayed implantation (a condition in which a fertilized egg reaches the uterus but delays its implantation in the uterine lining, sometimes for several months) and engage in seasonal breeding. Their breeding season is from late spring and early summer. The number of offspring ranges from three to 18. The average gestation period is one months. Young are altricial, meaning they are relatively underdeveloped at birth.Parental care is provided by females. The age in which young are weaned ranges from six to eight weeks. On average males and females reach sexual or reproductive maturity between three to 12 months.

Little is known about reproductive behavior of Yellow-bellied weasels. A den is built in a hole in the ground or under rocks or logs. If reproductive behavior is similar to that of their close relative, ermines (stoats), then breeding occurs annually with in late spring or early summer and implantation of fertilized eggs delays birth until the following spring. Females are therefore pregnant for approximately 10 months but gestation time is closer to one month in duration. Births occur in April and May. Again, if reproduction in yellow-bellied weasels is similar to that in ermine then young are blind and helpless at birth but increase in size rapidly until about eight weeks of age, when they are capable of hunting on their own. Females care for their young in the den until they gain independence. |=|

Mountain Weasels

Mountain weasels (Mustela altaica) are also known as the pale weasels, Altai weasels and solongoi. They live primarily in high-altitude environments, as well as rocky tundra and grassy woodlands in parts of Asia from Kazakhstan, Tibet, and the Himalayas to Mongolia, northeastern China and Korea, and southern Siberia. They are most common in Ladakh, India. These weasels rest and mae dens in rock crevices, tree trunks, and abandoned burrows of other animals or animals it previously hunted. Six subspecies have been described, each with a specific, restricted range.

Mountain weasels lives chiefly in mountains at elevations up to 3,500 meters (11,483 feet) and probably higher. They are seen most often in mixed taiga, highland steppes, or above timberline among heaps of stones. They have also been seen in sandy dunes, among reeds in wetlands and agricultural areas. They may set up dens near human habitations and occasionally attack domestic fowl. But overall mountain weasles are considered beneficial in agricultural areas because they prey on rodents that can be agricultural pests. Some trade of fur occurs, but pelts generally their pelts have low value and fur is usually dyed.[Source: Ellen Sherrill, Animal Diversity Web (ADW) |=|]

mountain weasel

On the International Union for Conservation of Nature (IUCN) Red List mountain weasels are are listed as Near Threatened because they are considered to be in significant decline and requires monitoring mainly because of habitat and resource loss.. In CITES (Convention on International Trade in Endangered Species of Wild) they have no special status. It is believed the average lifespan of mountain weasels is less than two years. Some populations experience extreme fluctuations, apparently depending on prey abundance and food conditions. Mass mortality may occur due diseases, fires or severe weather. Predators of mountains weasels have not been reported but may be owls, eagles and hawks. Mustelids in general are known for putting up a good fight and tend to be avoided by terrestrial mammalian predators such as wolves and foxes.

Mountain Weasel Characteristics, Diet and Predators

Mountain weasels range in weight from 122 to 350 grams (4.3 to 12.33 ounces) and have a head and body length that ranges from 21.7 to 28.7 centimeters (8.5 to 11.3 inches). Sexual Dimorphism (differences between males and females) is present: Males are larger than females. Males have a head and body length of 22 to 29 centimeters (8.7 to 11.5 inches), with a 11-to-15 centimeter (4.4 to 6.1 inch) tail, and weigh from 217 to 350 grams (7.6 to 12.33 ounces). Females have a head and body length of 22 to 25 centimeters (8.7 to 10.1 inches), with a 9-to-12 centimeter (3.7 to 4.8 inch) tail, and weigh from 122 to 220 grams (4.3 to 7.8 ounces). [Source: Ellen Sherrill, Animal Diversity Web (ADW) |=|]

Mountain weasels generally resembles Siberian weasels except they are smaller, and have shorter fur and a less luxuriant tail. They undergoes spring and autumn molts. The winter coat is dark yellowish to ruddy brown on the back, with pale yellow to creamy white on throat and belly. The upper head between the muzzle and ears is usually darker gray-brown. The tail may be more rufous than the back. the summer fur is gray to gray-brown with some light yellow. The lips of these weasels are white, and the chin has grayish-brown to whitish vibrissae (whiskers). Subspecies of mountain weasels are differentiated by fur color, which is generally a darker or lighter version of the colors described above.

Mountain weasels are primarily carnivores (eat meat or animal parts) and also recognize as sanguivores (consume blood) and insectivores (eat insects). Animal foods include small mammals, birds, amphibians, reptiles, eggs, blood, insects and non-insect arthropods such as spiders. Voles and pikas make up a large portion of the mountain weasel's diet. They may also prey on muskrats, ground squirrels, young rabbits, small birds, lizards (during summer months), and to a lesser extent frogs, fish, and insects. Mountain weasels have been observed eating juniper berries in some regions. The diet of captive weasels suggests that adult males need 45-54 grams of meat (3-4 domestic mice) a day. It is believed they may kill considerably more than that in the wild. When rodents prey is plentiful, these animals are thought to eat only the blood and brains.

Mountain Weasel Behavior and Reproduction

mountain weasel range

Mountains weasels terricolous (live on the ground), nocturnal (active at night), crepuscular (active at dawn and dusk), motile (move around as opposed to being stationary) and sedentary (remain in the same area). They are chiefly nocturnal but occasionally hunt during the day. They are very quick and agile, and good swimmers and climbers. When threatened they may make loud chirring sounds and eject a strong-smelling secretion from their anal glands. They are usually solitary but may be social, especially during the mating season. Sometimes sibling hang together after they are dispersed from their mother’s den until the end of their first summer. [Source: Ellen Sherrill, Animal Diversity Web (ADW) |=|]

Mountains weasels sense and communicate with vision, touch, sound and chemicals usually detected by smelling. Vocalizations are made when animals are threatened. Tactile communication occurs between rival males, between mates, and between a mother and offspring. Chemical communication occurs in all of the stinky mustelids.

The mating system of mountain weasels has not been described but it assumed to be similar to closel-related species like Siberian weasels. It is believed to be Mountains weasels are polygynous (males have more than one female as a mate at one time) and employ delayed implantation (a condition in which a fertilized egg reaches the uterus but delays its implantation in the uterine lining, sometimes for several months) but appear to do it for as long as some weasel species. Males probably compete for access to females, and the fights are probably quite fierce based how nasty weasels can be with their prey.

Mountain weasels engage in seasonal breeding — once annually. The breeding season in Kazakhstan occurs in February or March. The gestation period ranges from 30 to 49 days. The number of offspring ranges from one to eight. Young are seen at the beginning of May. The variablility reported for the length of gestation may be due to delayed implantation. Weasel young are born helpless, with closed eyes and little fur and are carred for in a burrow by their mother. Parental provisioning and protecting are done solely by females. Mountain weasel mothers nurse their young for approximately two months, at which time the young become independent. After independence sibling may remain together until fall. |=|

Itachi (Japanese Weasel)

The “itachi” (Mustela itatsi), or Japanese weasel, is endemic to Honshu, Shikoku and Kyushu and has been introduced to other islands as a means of controlling the rodent populations there. A carnivore, it thrives in both the country where they often feed on snakes, frogs, crayfish and crabs from rice paddies, and in urban areas, where they feed on mice and large insects such as grasshoppers. Siberian weasel have been introduced to Japan and in some places are displacing Japanese natives.

Kevin Short wrote in the Daily Yomiuri: Once in a while a lucky observer in the Japanese countryside catches a fleeting glimpse of a small brown animal darting along an irrigation ditch. With a long, narrow tubular body and short legs, and able to run very fast and very low to the ground, this is an itachi, or Japanese weasel. As is the case with many Japanese mammals, the itachi's natural distribution includes Kyushu, Shikoku and Honshu but not Hokkaido. [Source: Kevin Short, April 5, 2012]

Out here in the rice paddy countryside of northern Chiba Prefecture, I most frequently spot weasels along the drainage canals that run through the center of the valleys. Here fish, frogs, crabs and crayfish are plentiful in and around the water, and rodents and small birds hide in the tall grasses that flourish on the banks. The Japanese itachi, however, also eats many fruits and berries available in the nearby fields and thickets, and in some areas may even be an important disperser for plant seeds.

Stoats (Ermine)

Ermine (Mustela erminea) are also called stoats, short-tailed weasels and Bonaparte weasels. They are a northern weasel species that turn white in the winter. Widely distributed across northern North America and Eurasia, ermines are most abundant in thickets, woodlands, and semi-timbered areas. These slender, agile, voracious mammals have head and body length of measure 13 to 29 centimeters (5 to 12 inches). Their lifespan in the wild is as high as seven years but is typically less than two years. They have lived up to 12.5 years in captivity. The term “ermine” also describes the animal’s pelt and white winter fur has long been used in trimming coats and making stoles and was used historically in royal robes and crowns in Europe. [Source: Encyclopedia Britannica]

Ermine have a circumpolar distribution. They are found above the Arctic Circle and 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, central Europe and Central Asia. Ermine are absent from the Great Plains in the U.S. but are common in the British Isles and live in tundra, taiga, savannas, grasslands, forests, scrub forests, mountains, areas adjacent to rivers and other water bodies. |=|

Ermine prefer riparian woodlands near rivers, marshes, shrubby fencerows, and open areas adjacent to forests or shrub borders. Although ermine are primarily terrestrial, they are good tree cilbers and swimmers. Tree roots, hollow logs, stone walls, and rodent burrows are used as dens. Dens are usually around 30 centimeters 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. [Source: Heather Loso, Animal Diversity Web (ADW) |=|]

Black-Striped Weasels

Stripe-backed weasels (Mustela strigidorsa) belong to the musteleid (or weasel) family, which also includes otters, badgers, wolverines, and skunks. They are found throughout eastern Asia, with a range that extends from the eastern Himalayas into southern China and the northern Southeast Asia. Weasels, ferrets, minks, sables, martens and polecats are closely related. Stripe-backed weasels are often misidentified but confirmed sightings have occured in northern India, central Myanmar, southern China, northern Thailand and central and northern Laos and Vietnam. The southern limit of the species is not known. [Source: Reynaud Stewart, Animal Diversity Web (ADW) /=]

Stripe-backed weasels live in temperate and tropical land environments in thick jungle, evergreen forests, dense hill jungle, scrubby regenerating forest, river valleys, mountains and temperate forests at elevations from 90 to 2500 meters (295.28 to 8202.10 feet). Their habitat preferences have been largely inferred from the hunting by indigenous people. Those living at low altitudes appear to prefer rugged terrain.

Stripe-backed weasels are widespread, but do not appear to exist in large numbers. The International Union for Conservation of Nature (IUCN) Red List classifies them as a species of “Least Concern”. They are considered an endangered species in China and have protected status in Thailand. Stripe-backed weasels are trapped and hunted for food and fur by indigenous populations in Asia, although some indigenous people describe their meat as foul-smelling. Their pelts are not very value; only 3,000 to 4,000 documented pelts were harvested per year, in China during the 1970s. There have been reports of stripe-backed weasels killing domestic chickens, but the accuracy of these reports is questionable because they are often confused with mongooses and other small carnivores.

Least Weasels

Least weasels (Mustela nivalis) are also called little weasels, common weasels, or simply weasels. They are the smallest weasels and the smallest member of the genus Mustela. One of the world’s most widespread mammals, they are found in most of the Northern Hemisphere — in Asia, Europe, North America and North Africa, and have been introduced to New Zealand, Malta, Crete, the Azores, and São Tomé. [Source: Wikipedia]

Least weasels vary greatly in size over their range. Their body is slender and elongated, and their legs and tail are relatively short. Colour varies geographically, as does the pelage type and length of tail. The back, surface, flanks, limbs and tail of the animal are usually some shade of brown while the underparts are white. The line delineating the boundary between the two colours is usually straight. At high altitudes and in the northern part of their range, their coat becomes pure white in winter. Eighteen subspecies are recognised.

Least weasels are not endangered. They are designated as a species of least concern on the International Union for Conservation of Nature (IUCN) Red List due to their wide distribution and large population throughout the Northern Hemisphere and have no special status on the Convention on International Trade in Endangered Species (CITES). Least weasels help humans by preying on rodents, which can transmit disease, eat crops, and cause property damage. On the other hand they are also blamed for attacks on domesticated chickens and other avian livestock but is seems that while it does happen it doesn’t happen so much. Least weasels are not targeted by trappers by they are caught as bycatch in traps set fur-bearing mustelids like minks and sables. Least weasel pelts do not have a high economic value but they are used as lining and trim on garments such as luxury coats and mittens. least weasels are more common in Europe and Asia, While they are not considered rare in North America, and are not globally threatened. As a whole, populations of least weasels are considered stable. [Source: Gina Campbell, Animal Diversity Web (ADW) |=|]

Some weasel species: 39) Amazon Weasel (Mustela africana), 40) Altai Mountain Weasel (Mustela altaica), 41) Ermine (Mustela erminea), 42) Steppe Polecat (Mustela eversmanai), 43) Colombian Weasel (Mustela feliper), 44) Long-tailed Weasel (Mustela frenata), 45) Japanese Weasel (Mustela itatsi), 46) Yellow-bellied Weasel (Mustela kathiah), 47) European Mink (Mustela lutreola), 48) Indonesian Mountain Weasel (Mustela lutreolina), 49) Black-footed Ferret (Mustela nigripes), 50) Least Weasel (Mustela nivalis), 51) Malay Weasel (Mustela nudipes), 52) European Polecat (Mustela putorius), 53) Siberian Weasel (Mustela sibirica), 54) Back-striped Weasel (Mustela strigidorsa), 55) Egyptian Weasel (Mustela subpalmata), 56) American Mink (Neovison vison), 57) Patagonian Weasel (Lyncodon patagonicus)

Image Sources: Wikimedia Commons

Text Sources: Animal Diversity Web animaldiversity.org ; National Geographic, Live Science, Natural History magazine, CNTO (China National Tourism Administration) David Attenborough books, New York Times, Washington Post, Los Angeles Times, Smithsonian magazine, Discover magazine, The New Yorker, Time, BBC, CNN, Reuters, Associated Press, AFP, Lonely Planet Guides, Wikipedia, The Guardian, Top Secret Animal Attack Files website and various books and other publications.

Last updated June 2025