The sea mink (Neogale macrodon) is a recently extinct species of mink that lived on the eastern coast of North America around the Gulf of Maine on the New England seaboard. It was most closely related to the American mink (Neogale vison), with continuing debate about whether or not the sea mink should be considered a subspecies of the American mink (as Neogale vison macrodon) or a species of its own. The main justification for a separate species designation is the size difference between the two minks, but other distinctions have been made, such as its redder fur. The only known remains are bone fragments unearthed in Native American shell middens. Its actual size is speculative, based largely on tooth remains.
The sea mink was first described in 1903, after its extinction; information regarding its external appearance and habits stem from speculation and from accounts made by fur traders and Native Americans. It may have exhibited behavior similar to the American mink, in that it probably maintained home ranges, was polygynandrous, and had a similar diet, though more seaward-oriented. It was probably found on the New England coast and the Maritime Provinces, though its range may have stretched further south during the last glacial period. Conversely, its range may have been restricted solely to the New England coast, specifically the Gulf of Maine, or just to the nearby islands. The largest of the minks, the sea mink was more desirable to fur traders and became extinct in the late 19th or early 20th century.
Taxonomy and etymology
thumb|right|The closely related American mink (Neogale vison)|alt=A wet American mink with pale brown fur, dark brown eyes, long fingers, and a skinny tail. Its head is turned to the right and it is standing on a rock next to water.
The sea mink was first described as Lutreola macrodon, distinct from the American mink, by Daniel Webster Prentiss, a medical doctor and ornithologist, in 1903, after it became extinct. Prentiss based his description on skull fragments recovered from Native American shell middens in New England. Most sea mink remains, nearly all of them skull fragments, have come from shell middens, but a complete specimen has never been found.
Debate has occurred regarding whether the sea mink was its own species, or another subspecies of the American mink. Those who argue that the sea mink was a subspecies often refer to it as Neovison vison macrodon. A study in 1911 by Frederic Brewster Loomis, an American paleontologist, concluded that the differences between the American mink and the sea mink were too minute to justify the latter's classification as a separate species, and he named it Lutreola vison antiquus. A study conducted in 2000 by Mead et al. refuted Loomis by claiming that the size range for the largest sea mink specimen was beyond that of the American mink, thereby making it a separate species.
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The taxonomy of the minks was revised in 2000, resulting in the formation of a new genus, Neovison, which includes only the sea mink and the American mink. Formerly, both minks were classified in the genus Mustela. The species name macrodon translates to "large teeth". According to Richard Manville, a naturalist who maintains that the sea mink is not a separate species, its closest relative is the common mink (N. v. mink), which also inhabits the New England area.
Fur traders who hunted it gave the sea mink various names, including water marten, red otter, and fisher cat. Possibly the first description of this species was made by Sir Humphrey Gilbert
in the late 1500s as "a fish like a greyhound", which was a reference to its affinity for the sea and its body shape and gait, which were apparently similar to that of a greyhound. It is possible that the fisher (Pekania pennanti) got its name from being mistakenly identified as the sea mink, which was also known as the fisher by fur traders. The Abenaki Indians referred to it as the "mousebeysoo", which means "wet thing". Though it is speculated that they at one point inhabited Connecticut and Rhode Island, they were commonly trapped along the coast of the Bay of Fundy (in the Gulf of Maine), and it is said that they formerly existed on the southwestern coast of Nova Scotia. Sea mink bones have been unearthed in Canada, although these may have been carried there by Native Americans from the Gulf of Maine. The rugged shorelines of the Down East region of Maine may have represented a northernmost barrier in their range. It is thought that naturalist Joseph Banks encountered this animal in 1776 in the Strait of Belle Isle, and he described it as being slightly larger than a fox, having long legs, and a tail that was long and tapered toward the end, similar to a greyhound. In 1929, Ernest Thompson Seton, a wildlife artist, concluded that the probable dimensions for this animal are from head to tail, with the tail being long. A possible mounted sea mink specimen collected in 1894 in Connecticut measured from head to tail and the tail was in length; a 1966 study found this to be either a large American mink or possibly a hybrid. The specimen was described as having coarse fur that was reddish-tan in color, though much of it was likely faded from age. It was darkest at the tail and the hind limbs, with a white patch between the forearms. There were also white spots on the left forearm and the groin region. 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. Mead, concluding that the mink was restricted to nearshore islands, suggested that the large size was due to insular gigantism. Since almost all members of the subfamily Mustelinae exhibit sexual dimorphism, male sea minks were probably larger than female sea minks. The sea mink's wider carnassial teeth and blunter carnassial blades suggest that they crushed hard shells more often than did the teeth of the American mink.
Behavior
thumb|The sea mink was an [[Intertidal zone|intertidal predator of the Gulf of Maine.|alt=A sandy beach at dusk the sand on the bottom half, and the water and the horizon on the top half. There's a group of people walking across the shoreline, and on the right side of the picture there's a rock formation jutting upwards from the sand with evergreen trees on it]]
Although not a truly marine species, being confined to coastal waters, the sea mink was unusually aquatic compared to other members of Musteloidea, being, next to otters, the most aquatic member of the taxon. Remains of toad sculpins and ocean pout were the most common around their dens, and garden banded snails were also reported to have been part of their diet. although the 1894 kill is speculated to be of large American minks. Males were more often collected than females.