Long and narrow, with a very flexible spine, a relatively long neck, short limbs and a narrow skull, with quite an impressive set of teeth. Wild ferret hair is dark on the outer shaft and light at the base, with a light undercoat. The general color gets lighter on the head and especially toward the muzzle, but there is a dark mask across the eyes. The subspecies that is called the domestic ferret has many shades of dilution, even to being white. The white forms are not albino, for the eyes remain black.
True albinos lack all melanin, in their eyes as well as hair, so their eyes are pink.
The legs, from elbows and knees down, plus the tail tip and mask, are black. Black-footed Ferrets depended almost completely on Prairie Dogs. Weasels and polecats are generally active day or night and are little bothered by weather because they hunt primarily under ground or under the snow. All mustelids have anal glands with powerful musk. A little musk is passed with the fecal mass, which is carefully placed as a sign post where passing individuals are likely to find it.