A slim, agile mustelid that can pursue prey through tunnel systems too narrow for any rabbit-sized predator. They're also one of the few mammals where females reach sexual maturity before being weaned (yes, really).

Also called: Long-tail

Native status: Native; widespread

§ Quick facts

SizeBody 23–34 cm (9–13 in); tail 10–18 cm
WeightMales 160–340 g; females 85–200 g
LifespanWild typically 3–5 years
OrderCarnivora
FamilyMustelidae

§ Encyclopedia

The long-tailed weasel, also known as the bridled weasel, masked ermine, or big stoat, is a species of weasel found in North, Central, and South America. It is distinct from the short-tailed weasel, also known as a "stoat", a close relation in the genus Mustela that originated in Eurasia and crossed into North America some half million years ago; the two species are visually similar, having long, slender bodies and tails with short legs and a black tail tip.

Source: Wikipedia — Long-tailed weasel Licensed under CC BY-SA 4.0

§ Identification

Field marks. Long slim body with brown back and yellowish-white belly (summer); pure white with black-tipped tail (winter, northern). Considerably larger than other US weasels.

Similar species. Short-tailed Weasel/Ermine (smaller, shorter tail). Least Weasel (much smaller, no black tail tip). American Mink (much larger, dark brown year-round).

Voice. Hisses, screeches, chitters.

§ Diet & behavior

Diet. Small mammals (mice, voles, chipmunks, rabbits up to twice their own size), birds, eggs, occasional reptiles and amphibians.

Behavior. Most widely-distributed New World weasel. Northern populations turn white in winter except black-tipped tail; southern populations stay brown year-round. Hunts both by day and night; can follow prey into tight burrows. Climbs and swims well. Extreme metabolism requires eating ~30% of body weight daily — a single weasel may kill far more prey than it eats during high-population years.

§ Range

Throughout most of North America

§ Habitat

Diverse habitats from forest to grassland, often near water

§ Threats

Vehicle strikes, secondary rodenticide poisoning, climate-driven coat-color mismatch.

§ Conservation status

According to the IUCN Red List, the long-tailed weasel is currently classified as Least Concern.

§ What helps

Avoid second-generation rodenticides. Drive carefully on rural roads. Support climate action.

Support our work More ways to help

§ Further reading

§ Sources cited

  • American Society of Mammalogists
  • National Park Service
  • IUCN Red List 2016