Mustelids(Mustelidae)-is the largest family within Carnivora and is comprised of 56 species in 22 genera. Members of this family include weasels, stoats, polecats, mink, marten, fishers, wolverines, otters, badgers and others.


Adult mustelids range in size from 114 mm and 25 g (Least weasel) to over 1 m and 45 kg (Sea otters). These animals are generally long-bodied with short legs. Most species have slender bodies, but some, like badgers (Mustelinae, Mustelinae) and wolverines have much broader bodies. The skull is elongate with a relatively short rostrum. Adult males are generally about 25 percent larger than females of the same species. The ears are short, as are the legs, each of which bears five digits. The claws do not retract and, in digging species, are especially robust. The canines are long, and the carnassials are well-developed. The upper molars are often narrow in the middle, giving them an hourglass shape. Mustelids have a powerful bite; in many species, the large postglenoid process locks the lower jaw into the upper, causing the lower jaw to only move in the vertical plane, without any rotary motion.


Members of the family Mustelidae inhabit all continents except Antarctica and Australia. They do not occur on Madagascar or oceanic islands, but have been introduced to New Zealand.


Mustelids are primarily carnivorous, but some species may at times eat plant material. A wide range of animal taxa are preyed upon by various members of this family; many mustelids are opportunistic feeders rather than specialists. However, many mustelids are especially adept at capturing small, mammalian prey. Weasels, for example, are capable of chasing and capturing rodents in their burrows. Otters are well-adapted to chasing and capturing aquatic prey, including fish, crustaceans, and other aquatic invertebrates. Mustelids hunt in a variety of terrestrial, aquatic, and arboreal habitats. Some species regularly prey on animals larger than themselves. Some species have been known to store food.

In wild

Members of the family Mustelidae are either diurnal or nocturnal. Many of the long, narrow-bodied species are quick and agile, and move in a bounding, scampering fashion. The broader-bodied forms have a more lumbering gait. Some species are adept climbers, while others are excellent swimmers. Many species spend a great deal of time on the ground, searching for food in crevices, burrows, or under cover. Manyspeciesshelterinburrows.

Social behavior varies both within and among species, and may vary in relation to local environmental conditions such as food availability. For example, European badgers are known to form groups with several males and females that are all reproductively active within the group. Yet in other parts of their range, European badgers may live solitarily or in pairs.

Mating systems vary both within and among species. Many species are polygynous and/or promiscuous. Some species are social, while others are solitary. Social organization can vary within species as well. Most mustelids breed seasonally, but the length of the reproductive period varies among species. Day length often dictates the onset of the breeding season, which usually lasts 3 to 4 months. Many mustelids undergo delayed implantation, with the fertilized embryo taking up to 10 months (e.g. Melesmeles) to implant in the uterus in some species. Environmental conditions such as temperature and day length determine when implantation occurs. Mustelids that live in more seasonal climates are more likely to exhibit delayed implantation. Following implantation, gestation typically lasts 30 to 65 days.

Females give birth to a single litter each season, the size of which varies within and among species. For example, sables have an average litter size of 2.2, but can give birth to anywhere from 1 to 7 pups. The mountain weasel averages 8.7 pups per litter, but can have between 3 and 14 young in a single bout of reproduction. Generally, mustelids are altricial, being born small and blind. They reach sexual maturity between 8 months and two years following birth.

Mustelids typically live between 5 and 20 years in the wild.


Martes flavigula

Males measure 500–719 mm (19.7–28.3 in) in body length, while females measure 500–620 mm (20–24 in). Males weigh 2.5–5.7 kg (5.5–12.6 lb), while females weigh 1.6–3.8 kg (3.5–8.4 lb).

One individual lived 16 years in captivity.

Mustela sibirica

Adult males are 28–39 cm (11–15 in) long, while females reach 25–30.5 cm (9.8–12.0 in). The tail in males reaches 15.5–21 cm (6.1–8.3 in) in length, while that of females reaches 13.3–16.4 cm (5.2–6.5 in). Males weigh 650–820 g (23–29 oz), while females weigh 360–430 g (13–15 oz).

In the wild, an average longevity of 2.1 years. One captive specimen lived 8.8 years

Martes foina

Males measure 430–590 mm in body length, while females measure 380–470 mm. The tail measures 250–320 mm in males and 230–275 mm in females. Males weigh 1.7–1.8 kg in winter and 2–2.1 kg in summer, while females weigh 1.1–1.3 kg in winter and 1.4–1.5 kg in summer.

Martes martes

Its body is up to 53 cm (21 in) long, with a bushy tail of about 25 cm (10 in). Males are slightly larger than females; typically, it weighs around 1.5–1.7 kg (3.3–3.7 lb).

Pine marten has lived to 18 years in captivity, but in the wild, they can live up to 11 years. 

Martes zibellina

Males measure 38–56 centimeters (15–22 in) in body length, with a tail measuring 9–12 centimeters (3.5–4.7 in), and weigh 880–1,800 grams (1.94–3.97 lb). Females have a body length of 35–51 centimeters (14–20 in), with a tail length of 7.2–11.5 centimeters (2.8–4.5 in).

Meles meles

Adults measure 25–30 cm (9.8–11.8 in) in shoulder height, 60–90 cm (24–35 in) in body length, 12–24 cm (4.7–9.4 in) in tail length, 7.5–13 cm (3.0–5.1 in) in hind foot length and 3.5–7 cm (1.4–2.8 in) in ear height. Males (or boars) slightly exceed females (or sows) in measurements, but can weigh considerably more. Their weights vary seasonally, growing from spring to autumn and reaching a peak just before the winter. During the summer, European badgers commonly weigh 7–13 kg (15–29 lb) and 15–17 kg (33–37 lb) in autumn.

The maximum life expectancy is about 14 years.

Gulo gulo

The adult wolverine is about the size of a medium dog, with a length usually ranging from 65–107 cm (26–42 in), a tail of 17–26 cm (6.7–10.2 in), and a weight of 5.5–25 kg (12–55 lb).

The typical longevity of a wolverine in captivity is around 15 to 17 years.

Mustela erminea

On average, males measure 187–325 mm (7.4–12.8 in) in body length, while females measure 170–270 mm (6.7–10.6 in). 

Males average 258 grams (9.1 oz) in weight, while females weigh less than 180 grams (6.3 oz).

The average life span of a stoat is 1 to 2 years; the maximum is 7 years.

Aonyx cinerea

In head-to-body length, it ranges from 470 to 610 mm (18.4 to 24 in) with a 260 to 350 mm (10.2 to 13.6 in) long tail.

Asian short-clawed otters live up to 12 years in human care, with some individuals living longer than 20 years.

Mustela nivalis

Average body length in males is 130 to 260 mm (5 to 10 in), while females average 114 to 204 mm (4.5 to 8.0 in). The tail measures 12 to 87 mm (0.5 to 3.4 in) in males and 17 to 60 mm (0.7 to 2.4 in) in females. Males weigh 36 to 250 g (1.3 to 8.8 oz), while females weigh 29 to 117 g (1.0 to 4.1 oz).

The average lifespan for wild individuals is short; only 1 or 2 years, whereas the longest recorded captive lifespan is 10 years.