These minks were large and heavily built, with a low sagittal crest and short, wide postorbital processes (projections on the frontal bone behind the eye sockets).[1] In fact, the most notable characteristic of the skull was its size, in that it was clearly larger than that of other mink species, having a wide rostrum, large nostril openings, large antorbital fenestrae (openings in the skull in front of the eye socket), and large teeth.[2] Their large size was probably in response to their coastal environment, as the largest extant subspecies of American mink, the Alaskan mink (N. v. nesolestes), inhabits the Alexander Archipelago in Alaska, an area with a habitat similar to the Gulf of Maine.