Although creatures in the weasel family are often just called weasels, they are actually split up into a variety of species. You might be seeing an ermine, otherwise known as a stoat or short-tailed weasel, (Mustela erminea), the least weasel (Mustela nivalis) or a mink (Mustela vison).

Photo of a short-tailed weasel

Ermine

If you see one, though, how do you know which one you’re seeing?

Tail

Ermines can easily be identified by the black tip on their tail. It is most noticeable when they have white winter coloring, but it also exists with its brown summer coat.

Ermine, photo by Steven Hint, via Wikimedia Commons

The least weasel, which is becoming ever-increasingly rare in Iowa, and the mink both lack a black tail tip.

Photo of a least weasel

Least weasel, photo by Keven Law, via Wikimedia Commons

Mink and ermine both have a tail that is about a third of their body length, whereas the least weasel’s tail is a little bit shorter — about a quarter of its body length.

Size

Mink are generally larger than other weasels. Mink average 13-18 inches long and weigh up to 3 pounds, whereas ermine weigh 0.2-0.3 pounds and least weasels weigh 1-2 ounces.

Color

Mink can be brown or black, but many mink in Iowa are black year-round. An ermine is dark brown in summer with a white belly, feet and a white line down its hind leg. It turns white in the winter. The least weasel has a reddish brown back, sides, tail and top of head with white underparts. It also turns white in the winter.

Habitat

Although mink, ermine and weasels all like to live in bottomlands, mink always live near water. They have semi-webbed feet that make them great swimmers.

Photo of a mink

Mink, photo by Steven Hint, via Wikimedia Commons

Check out some of our other blogs that help you differentiate between creatures:
Chorus frogs vs. leopard frogs
Coyotes vs. wolves
Osprey vs. bald eagles
Moth vs. butterfly
Finches

11 Comments

  1. Brad on April 13, 2020 at 10:21 pm

    We saw a small ermine today. Hood Canal. Washington state.

  2. Mike Hock on April 7, 2020 at 8:26 pm

    I saw a brown mink with a white spot on its chest at my pond today!

  3. tony h on March 22, 2020 at 3:00 pm

    Just saw a ( not sure) running along my stone wall. It’s March this was all white with black tipped tail. This was 16″ long so I’m guessing mink but this article does not mentionmink with black tipped tails. It sounds like Ermine’s are small enough to separate from mink. So was it a mink or not? It was in pursuit of a chipmunk.

    • kiley on March 23, 2020 at 2:04 pm

      That sure sounds like an ermine!

  4. Donald Huschle on February 19, 2020 at 8:27 pm

    WOW, I didn’t think cats could kill weasels. I grew up on a farm and weasels killed our chickens and our cats didn’t get them. Maybe easier prey. We never feed our cats. Belief was if you fed cats they wouldn’t mouse. Here in Dallas we have coyotes now and they eat cars. Didn’t think they could catch or would eat cats but they are resourceful.

  5. Patty on February 18, 2020 at 8:22 am

    Just found an ermine in the snow on our walkway- cat probably brought home
    Sodus NY
    A first since living here (1983- now)

  6. Virginia Harrison on December 18, 2019 at 9:21 pm

    Just found an ermine….white with black tail….in my laundry room that the cat killed. How it got into the house is a mystery. I live west of Helena, MT in a area surrounded by forest lands, ranches and a nice size reservoir. This is the first time I seen one of these.

    • Carrie Lawrence on December 22, 2019 at 1:08 pm

      Me too! There is an active one in my kitchen right now. Way smarter than mice, so my cats are figuring out what to do about it. Currently, it seems to be hiding behind the dish washer. We have seen field weasels here in Troy, ID before, but I have never seen a white ermine. They have a super musky smell I am not happy about!

  7. Angie on July 25, 2019 at 8:57 pm

    My cat killed a weasel & left it on our door step yesterday, we live in central Idaho on the upper Salmon river.

    • Amy Leaf on December 7, 2019 at 11:52 am

      My dog just brought home an Ermine.. 12/7/19 upper Michigan

  8. Gay Eyman on May 20, 2019 at 10:51 pm

    Our cat killed an animal that looks exactly like a least weasel. It is the second one we have seen this year and have never seen one before in the 11 years of living here. We are in Helena,Montana and just wondered if anyone else has this experience.

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