American mink are members of the mustelid family; related to species such as badgers, otters, polecats and stoats. In size, they are much smaller than an otter but larger than a stoat and similar in size to a polecat or domestic ferret. They are mostly a very dark brown, appearing almost black and may have a few white patches on their chin, throat, or underside. They may occasionally be other colours, such as a silvery grey. This variation relates to the breeding of American mink in various colour forms in fur farms, from which the ancestors of our feral American mink escaped or were released.