Weasels are slender, agile mammals, typically with red or brown fur above and white below. Their tail tip is usually black (with the exception of the least weasel), and the feet of the least and short-tailed weasel are white, while those of the long-tailed weasel are usually brown.
In winter, weasels in the northern parts of their range will develop an all-white fur coat, though the black tip of the tail remains. These white furred weasels are usually referred to as “ermine”.
The body length of the short and long-tailed weasels is about one foot in length. The tail of the short-tailed weasel is usually around four to five inches, while that of the long-tailed weasel can be as long as eight inches. The least weasel is much smaller, with a body length of five to ten inches and a tail that doesn’t grow longer than three and a half inches.