For the past half dozen years, at least, those who sit along the edges of the Cape Cod Canal, and keep their eyes open, are sometimes rewarded with the glimpse of a tail as a swift-moving, brown-coated animal comes out of the water and slips into a burrow built in the midst of the stony rip-rap.
They are American mink, and Carl A. Johansen of Sandwich, who has been fishing in the canal since 1946, said fishermen have been seeing them in larger numbers for the past four or five years.
Mr. Johansen said he has seen them swimming in the back eddies that form in some places on the mainland side of the canal when the tide changes. There (and then), he said, they do not have to battle the canal’s swift-moving currents.
Just as he knows to come out in the early morning hours to fish, so do the mink, he said.
He finds their presence a delight, particularly, he said, compared to the number of rats that used to infest that rip-rap. Mink are carnivores, and rodents are among the items on their diet.
He does not know if someone purposely brought the mink to the canal to feast on those rodents. He does recall, however, that a number of animals have been introduced for that purpose over the years, including, he said, ferrets. They, however, did not survive the region’s winters.
While domestic mink are now bred for fur, they were often bred for ratting in the late 19th century, according to a Wikipedia article.
Last summer, Mr. Johansen reported, he was fishing on the canal when a mink scrambled up the rip-rap, fish in mouth, and dived into a burrow some three feet from him. He was close enough, he said, to hear the mink family chattering.
He has spent a half hour “enthralled” watching as a mink went into and out of the water.
They have been reported in various spots along the length of the canal, said Samantha A. Gray of the US Army Corps of Engineers, which manages the waterway and its surrounds.
American mink belong to the same family as stoats and weasels, but they are larger and have bushier, tapered tails that are a third to half the length of their approximately two-foot long body.
The mink’s black or brown fur is broken by a bit of white fur on their chins, and a small bit on their throats.
They are not endangered and are found in Canada and almost every state in the union except for Hawaii and those like Arizona, New Mexico, and western Texas that are hot and dry.
The mink usually live near rivers, ponds, lakes, and marshes, as well as canals, eating fish and prey as large as muskrats and rabbits, along with rodents, frogs, birds and aquatic insects.
According to NatureWorks, an online educational version of a program developed by New Hampshire Public Television, mink are good swimmers who can dive as deep as 16 feet. They have what has been described as a very foul-smelling spray.
When a mink is happy, it makes a purring sound like a cat, according to NatureWorks, but it can also bite. Mink are very territorial, and males will challenge other males that invade their territory. April is mating season in the north. An average litter is four kits; they stay with the mother from their birth until autumn. By the following spring, they are mature enough to mate.
It reportedly can only withstand very cold water temperatures for less than a half hour, a limit that increases to three-hour swims in warmer waters. Mink swim with an undulating movement and have a bounding gait on land. They can reach speeds of up to 4 miles per hour.
Bourne residents Joanne Corsano and her husband, David Fleming, were down at the canal last Saturday, hoping to try out their new camera on the eider ducks that also inhabit the canal area. Instead, a mink living in the rip-rap came out to pose for them.
Mr. Johansen, who considers the mink a good sign, reflective of the health of the canal area, echoed that, saying they are “awesome to watch.”
He said there is a lot of wildlife to see on the Cape, from deer to fisher cats to mink, “if you keep your eyes open.”