During the last glacial period, ending 12,000 years ago, the sea mink's range may have extended south of the Gulf of Maine. It may have even evolved there, as Maine at that time would have been covered in glaciers, although the oldest known specimen only dates back to around 5,000 years; this could be due to the rising sea levels—older sea mink remains may be submerged underwater. Alternately, the sea mink may have evolved after the last glacial period and filled a new ecological niche.[1]