Females are 10-15 percent smaller than males and up to half a pound lighter. A mink's coat is thick, full and soft. A short, tight layer of underfur is covered with longer guard hairs, which give the pelt its luster. Colors range from russet to a deep, chocolate brown. Unlike some weasels, the mink does not turn white in winter.
Minks have excellent hearing and sight, and a good sense of smell.
On land, they travel at a slow, arch-backed walk or a bounding lope, which they can keep up for miles. Minks are most active at night and early morning, although they sometimes venture out during the day as well. Active year-round, minks may curl up and sleep for several days during winter cold spells. Like most mustelids, they are agile and fierce fighters, killing prey with a hard bite to the back of the skull. Prey includes muskrats, mice, rabbits, shrews, fish, frogs, crayfish, insects, snakes, waterfowl and other birds, eggs and domestic poultry.