Curious Nature: Stinky mink
Vail, CO Colorado
When I think of a mink, I envision a small, very soft, furry creature slithering along the river banks and frisking playfully along the shore. The reality couldn’t be farther from the truth. While mink are well-adapted for their aquatic habitat and can most often be found near water of some sort, they are not generally playful. In fact, mink are known to be quite fierce, especially if you’re a muskrat, and it is even fairly common for them to kill more than they can eat and save the leftovers in their den.
Now that we are thinking of mink as the vicious predators they are, we can begin to understand more about their world. And since we’re already talking about food, mink have voracious appetites. They will eat just about any small animal they can find, including mice, rats, showshoe hare, fish, frogs and even birds. They use their long necks and powerful jaws to kill prey instantly and sometimes even swallow small animals whole. Mink are well-suited for hunting in their aquatic homes, with their streamlined body and partially webbed feet, but they lack some of the special lung and eyesight adaptations that their otter cousins have, relegating them to keeping their dives short and sweet. Dive, snap, swallow, repeat.
Another reason you won’t see a group of happy mink frolicking on the river bank is because they are incredibly territorial. They live solitary lives in individual burrows, often an abandoned muskrat den or beaver lodge, although they may wander several kilometers daily in search of food. Like their relatives the skunks, mink have the ability to emit a foul odor when threatened. Unlike skunks, though, mink are unable to project this spray, sometimes leaving very ugly results. Males become very aggressive and territorial during the mating season, and despite predation by larger species such as bears or coyotes, the largest cause of mink mortality is in territorial battles with other males. This might be due, in part, to the females’ promiscuity. Females begin mating some time in February and continue to mate with different males through April. In fact, it is not uncommon for the young from a single litter to be fertilized by different males.
With spring in the air these days, mink, like many of their mustelid family cousins (weasels, skunks, badgers), are preparing to give birth. Mating occurs any time starting in late February, and then the female carries the fertilized eggs for between 10 and 45 days before they finally implant in the uterine wall. This phenomenon, known as delayed implantation, is thought to ensure the young are born at a time when food is most plentiful, regardless of the actual timing of mating. The young are born blind, helpless and covered only by a thin coat of fine white hair. After approximately two weeks, the white fuzz falls out to be replaced by a dull, fluffy, reddish-brown coat, which is again replaced by the famous adult pelt later in the first year. The young finally leave the nest when they are about 7 weeks old, shortly before they are weaned. It is at this point the young mink learn to hunt for themselves, joining their mother at first and eventually tackling small prey and learning to be vicious in their own right.
Because they are nocturnal and well-camouflaged, mink sightings are rare. Your best bet at spotting one is from a waterway, maybe as you calmly paddle downstream, succumbing to the whim of the currents. Suddenly, there’s a flash of chocolate brown fur scrambling across a downed log. Black, beady eyes make momentary contact with your own before the fleck disappears, sliding effortlessly and silently under the surface. The mink is gone as suddenly as it appeared, gliding stealthily away on its next hunting trip, leaving only memories, footprints and the remnants of its kills behind.
Jaymee Squires is the director of graduate studies at Walking Mountains Science Center. She has yet to spot a mink, but she plans to spend a lot of time looking this summer.