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).
If you see one, though, how do you know which one you’re seeing?
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.
The least weasel, which is becoming ever-increasingly rare in Iowa, and the mink both lack a black tail tip.
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.
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.
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.
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.