Weasels are small carnivores belonging to the genus Mustela, together with the two remaining species of mink, 17 species of ferrets, and the ermine.
Weasels have elongated tube-like bodies with short limbs, flattened heads, long necks, and slim tails with pointed tips. They are mainly popular in the Northern Hemisphere where they adapt due to short fur that is dense.
To help you know the different types of weasels, we are going to discuss five main types of weasels; their habitat, appearance, behavior, size, weight, and lifespan.
Stoat (Short-Tailed Weasel)
Stoat (Mustela erminea) also called ermine, is native to North America, Asia, and some parts of Europe. They also exist in New Zealand as introduced species of Weasels.
In winter, stoats grow thicker and silkier fur that is pure white except for the black tail. Historically, the white pelts were used in royal robes in Europe and also sold in the fur trade.
However, these animals are not in danger. In summers, ermines grow brown furs with whitish throat, chest, and belly.
Stoats are agile, slender, and voracious. They measure 13 to 29 cm (5-12 inches) in head and body length, while their tails measure 5 to 12 cm (2 to 4.7inches). Averagely, they weigh less than 0.3 kgs (0.7 pounds)—females are smaller and weigh less than males. Also, the Northern species are smaller than the southern counterparts
Male stoats demarcate territories using urine and feces to defend their female counterparts from other males. The animals prey on rodents and lagomorphs species such as pikas, European water voles, and common hamsters.
They do not build homes; instead, they take over nest chambers, burrows, old and rotting stumps, haystacks, bog hummocks, rock piles, and cleft from rodents they kill.
Stoats live 6-7 years, but a few survive more than 12-15 months. Even though stoats resist a wide range of diseases, they are vulnerable to tuberculosis, canine distemper, and ectoparasites such as flea species and nematodes.
Bridled Weasels (Long-Tailed Weasel)
Bridled weasels (Mustela Frenata) or big stoat are species of weasels that are mainly found in Southern Canada, the United States, and some parts of Mexico.
These types of weasels have distinct black eyes in daylight. During the night, when you spot their eyes with a flashlight, the eyes become emerald green.
They also have furs on their upper side that grow brown, especially during summers. The underparts are whitish with tiny yellow or buffy brown spots while the tail is pure black.
In winter, long-tailed weasels grow white furs, sometimes with yellow tings and black tail. Species in Florida and Southwestern US have either white or yellow facial tints. Unlike stoats, bridled weasels have thick furs all-year-round. They produce a strong and musky odor that emanates from the well-developed anal scent glands.
The species in Mexico are generally larger than their northern counterparts. The Mexican males measure 25-30 cm (9.8-11.8”) in head and body length, and 14-20 cm (5.5-8”) in tail length.
The Canadian and South American males measure 22.8-26 cm (8.9-10.2 “) head and body length, and 10.2 -51.2 cm (4-5.9”) tail length.
Averagely the females measure 20.3 -22.8 cm (7.9-8.9”) head and body length, and 7.6-12.7 cm (2.9 -5”) tail length.
Males weigh 198-340 g (7-12 oz) while females weigh 85-198 g (2-6.9 oz).
Bridled weasels mate in July-August. They have a gestation period of 10 months. When in danger, or when looking for mates, they produce a musky odor that scares enemies such as coyotes, wolves, wild cats, and the Canadian lynx.
As fearless and aggressive hunters, these species of weasels prey on animals even larger than themselves. They stalk and strike prey such as mice, rabbits, squirrels, shrews, moles, chipmunks, small birds, and popular reptiles.
Long-tailed weasels den in Chipmunk burrows, under stumps, and beneath rocks. They have a potential lifespan of 5 years.
The yellow-bellied weasel (Mustela Kathiah) has a yellow underbelly with a dark-brown fur that covers the upper side, to the tail. In terms of distribution, they are mostly found in China, India, Nepal, Pakistan, Vietnam, Thailand, Laos, Bhutan, and Burma.
These animals inhabit forested areas ranging between 1,000 to 2,000 meters above sea level. However, during winter, they migrate to the warmer regions lying 1,000 meters.
Yellow-bellied weasels measure 9.8-10.6 inches (25-27 cm) in body length and 4.9-5.9 inches (12-15 cm) in tail length. On average, males weigh 1.56 kg (3.44 lb). They build dens in the ground and prey on birds, voles, mice, rats, and other small animals.
These types of weasels are nocturnal, motile, territorial, and solitary. They communicate through touch and by producing smells and other chemicals.
Yellow-bellied weasels reproduce during the period between late spring and early summers. They have a gestation period of one month and can give birth to offspring ranging from 3-18 in number. At birth, the offspring is blind and helpless. However, it grows faster, by 8-weeks of age, they can prey on their own.
The female parents care for the young one until they become of age. Averagely, these weasels can live up to 8 years.
The least weasel (Mustela nivalis) is the smallest carnivore in North America. These invasive predators are native to Eurasia, North America, and North Africa. They also exist in New Zealand, Crete, Azores, Bermuda, and Malta as introduced species.
Least weasels have body colors that vary geographically. The flanks, limbs, tails, and dorsal surface are mostly brown, whereas the underparts are white. Species in the Northern Parts of the United States develop furs that are pure white during winters. So far, eighteen subspecies have been recognized across the world.
The weight and sizes of each weasel in every subspecies vary. The smallest weighs about 1 ounce (25 grams) and grows 4-10 inches (11-26 cm) in body length. The largest species of least weasels have body lengths ranging from 25 to 30 cm (10-12”). They weigh about 85 to 350 g (3 to 12.3 ounces). In adults, the tails lengths range from 10.2 to 20.3 cm (4-8 inches).
Least weasels inhabit grasslands, forests, suburbs, and villages where they feed on rats, rabbits, voles, mice, frogs, birds, and bird eggs.
Behaviorally, these weasels are curious, bold, and alert. They are persistent hunters that are more active at night. In most cases, they hunt in pairs except during the breeding and rearing seasons.
They are also good swimmers and can climb trees. All species emit a strong musk odor that they use as a mode of communication. Also, they mark their trails through droppings and can cover home ranges of about 30-400 acres.
Least weasels are prone to predation from hawks, foxes, coyotes, dogs, cats, and man. They have an average lifespan of about 8-years.
The Siberian weasel (Mustela sibirica) or Kolonok comes in a medium-sized body. This species of weasels is native to Asia, with a population distribution in Pakistan, India, Nepal, Bhutan, Myanmar, Thailand, Taiwan, China, North Korea, Laos, and some parts of Russia.
The Siberian Weasel inhabits secondary forests that are 1400-1700 m above sea level. They can also be found in primary forests and coniferous forests.
The Siberian Weasel has a pale brown back with an often-changing paler or yellowish-brown underside. The tip of the tail is darker, but not black like in other species we have mentioned above.
They also have legs that are the relatively short and elongated head that is narrower and relatively small. The ears form into broad bases for ease of hearing.
During winter, their fur is very dense, fluffy, and short. Some sub-species also have a dark-coffee brown mask on the face.
Males are 11-15 inches (28-39 cm) in body length, while adult females are 9.8-12.0 inches (25-30 cm). The tail in males is about 6.1-8.3 inches (15.5-21 cm), while females have tails measuring 5.2 -6.5 inches (13.3 – 16.4 cm) in length.
Unlike most weasels, the Siberian weasel builds its own nest inside fallen logs, brushwood piles, empty stumps, and exposed tree roots. They frequently prey on water voles, red squirrels, chipmunks, muskrats, and mice. They reproduce during different periods depending on their geographical distribution.
Siberian weasels are both nocturnal and crepuscular. They are territorial and often migrate in search of food. In a single night, they can move up to 8 km.
They are also motile, solitary, and sedentary. The Japanese sub-species have an average lifespan of 2.1 years, whereas the western subspecies live between 5-6 years.
Now, that you know about the most common types of weasels, next time you will be able to identify which weasel you see in your garden or in the woods.