Small Common Mustelids

You don't need to learn to seperately identity the species of all small mustelids - but, having a visual reference of common small mustelids to compare to your intake will help you determine if you need to contact a wildlife rehabilitation facility.

The most common small wild mustelids are American mink and long tailed weasels. These can both be roughly ferret sized, give or take. Other small mustelids include short tailed weasels (also known as stoats or ermine) and least weasels, which are practically mouse sized!

Less common small mustelids include black footed ferrets (which look and act VERY differently from domestic ferrets, and are highly endangered & rare) and martens, which are semi-arboreal and very fluffy.

Take a look through the following charts to familiarize your self with small wild mustelids native to North America!

Photo Reference Links

Facial Side Profile Comparison

Comparison graphic showing four small mustelids: a long-tailed weasel, a short-tailed weasel, an American mink, and a domestic ferret. Each animal is shown in side profile with labeled species names, highlighting differences in size, face shape, and body proportions.

Long Tailed Weasel Study

Educational graphic showing a long-tailed weasel in summer coat. Images include close-ups of facial markings and a full-body side view. Text highlights identifying features and notes that visual identification alone may be unreliable.

Seasonal Coat Transition in Weasels

Comparison graphic showing three long-tailed weasels in different seasonal coats: brown summer coat, partial color transition, and white winter coat. The images illustrate how coat color changes with season.

Variations in Weasel Facial Markings

Comparison graphic showing four long-tailed weasels with different facial markings: no mask, masked, mid-transition, and winter coat. Text notes that identification by facial markings alone may be unreliable.

North American Weasel Species Comparison

Comparison image showing three weasel species in side profile: least weasel, short-tailed weasel, and long-tailed weasel. Each animal is labeled to illustrate differences in body size, proportions, and tail length.

Black Footed Ferret

Comparison image showing a black-footed ferret in multiple views, including a full-body side profile and close-up views of the face. The images highlight the species’ pale body, dark facial mask, and darker legs and feet.

Marten and Fisher

Comparison image showing a marten and a fisher in natural woodland settings. Both animals are labeled to illustrate differences in body size, build, and overall appearance.