Long-Tailed Weasel

Mustela frenata
Bridled weasel, Big stoat
The Long-tailed weasel is an endearing-looking species of mustelid common throughout America and southern Canada. Looking like a cute, curious, lively kitten, it is one of nature's most ferocious and relentless predators and is known as "nature's psychopath." Due to the pattern of their hunting and fearless attitude about attacking bigger animals, they are an interesting animal to study. They secure extra prey for future consumption, driven simply by their basic instincts.

population size

8 yrs

Life span

25 km/h

Top Speed

80-450 g


28-42 cm



Long-tailed weasels occupy a wide range, from southwestern Canada south across the United States (except parts of the southwest) then into Central America, Mexico and South America (Columbia, Venezuela, Ecuador, Peru, and Bolivia). They are found in tropical and temperate habitats in Central and North America. Their habitats range from small wooded areas to crop fields to suburban areas but do not include thick dense forests or deserts. Their nests and burrows are in rock piles, hollow logs and under barns.

Habits and lifestyle

These mammals are not social animals and the genders live apart except in the mating season. A male’s home range will overlap those of several females, but those of same-gender adults never overlap. These animals are very aggressive when their home ranges are intruded. They are quick, alert and agile. They hunt their prey by detecting scent or sound, then follow their victim to attack quickly, killing them with a quick bite at the base of the animal’s skull. Long-tailed weasels may be active in the daytime but are more active during the night. They are known to be noisy, usually in response to a disturbance. This species communicates among themselves through visual, sound, and scent means. Females emit an appealing scent when ready to mate. Sounds and body language are used for communicating when two weasels confront each other.

group name

gang, colony, pack, sneak

Diet and nutrition

The Long-tailed weasels are carnivores. This species mainly eats rodents, but sometimes eats fruits, lizards, and small birds.


Mating habits

Long-tailed weasels are polygynous, which means that one male mates with multiple females. Mating takes place during mid-summer. After copulation, there is a period of delayed implantation, with the egg not beginning to develop until March, the total gestation time being around 280 days. Births are from late April through early May. The average litter size is six. At birth young weigh about 3 grams and have pink wrinkled skin with white fur. After fourteen days, their hair starts to thicken, and size-wise it is easy to tell males and females apart. At 36 days they are weaned and start eating food their mother brings back to the nest. Their mother teaches them how to kill prey and by 56 days they can kill their own prey. Females mate during their first summer, males the following spring.

Mating behavior

Reproduction season


Pregnancy duration

280 days

Independent age

36 days
bitch, doe, Jill

female name

dog, buck, Jack

male name

kit, pup

baby name

6 kits

baby carrying


Population Trend

Population status


Population threats

Long-tailed weasels are possibly sensitive to fragmentation of habitat due to agricultural activities, so maintaining landscape connectivity is important for this species. Other threats include the drainage of wetlands and monoculture. They may also be affected both directly and indirectly by the use of pesticides, through effects on habitat, reproduction and/or food supply.

Population number

Long-tailed weasel is widespread and fairly common throughout its range but no overall population estimate is available. Currently this species is classified as Least Concern (LC) and its numbers today remain stable.

Ecological niche

Due to what they consume, Long-tailed weasels help control populations of rabbits and rodents.

Fun facts for kids

  1. Long-tailed weasels are good swimmers and climbers.
  2. These animals have a well-developed sense of sight, hearing, and smell, enabling them to be sensitive and efficient predators.
  3. Long-tailed weasels evolved almost 2 million years ago in North America.
  4. Long-tailed weasels have such a high metabolic rate that they can eat around 40 percent of their body weight every day.
  5. Hungry Long-tailed weasels have no conscience and may kill and eat their siblings or offspring if there is no other food available.
  6. In colder parts of its environment, the weasel will use a good deal of its food simply to maintain body heat. To stay warm, it curls up in a tight circle.
  7. Unfortunately for weasels, they have been associated with politicians, who are said to "weasel out" of particular situations and use "weasel words" in their public statements, for political gain.
  8. In the north part of their range Long-tailed weasels turn white in winter, while in the south their coat is the same color year-round.


  1. Long-Tailed Weasel Wikipedia article
  2. Long-Tailed Weasel on The IUCN Red List site