Wild On The Prairie: Mammals
Know the Odoriferous and Ferocious: the Mustelidae
February 3, 2010
The Mustelidae includes weasels, minks, martens, fishers, black-footed ferrets, river otters, sea otters, skunks, badgers and wolverines. As a family, they fulfill the ideal of the predator. A “predator” is any organism, which is highly skilled and adapted to hunt and kill other organisms for food.
Members of the Mustelidae vary greatly in size. The smallest is a species of weasel which has a 6 to 8 inch body and weighs one to 2.5 ounces; the largest is a sea otter which has a four-foot body and weighs up to 100 pounds. Throughout the family, males are up to 100% larger than the females. One species of weasel is the smallest carnivore in the world: wolverines are 450 times larger.
At first I wondered how a family could include so many animals so varied in habitat preference, size and distribution. Anatomically they are very similar and most share one very conspicuous characteristic: the production of musk (must) from anal glands, which gives them their name Mustelidae. Ferrets are nice pets except they produce musk in copious amounts when disturbed or frightened. Burrows occupied by skunks, badgers, weasels and minks can be easily identified by their odor - all you need to do is get down arid sniff. Musk has many uses - it serves as a defensive weapon, a marker of food caches, as a form of chemical communication between animals of the same species, as a sexual device for locating potential mates, and to mark the boundaries of an individual’s territory.
Most family members possess only cutting or slashing teeth. (Sea otters have molars to crush the mollusks they eat in quantities.) They are all more or less near-sighted; their hearing is not exceptional but they have a very keen sense of smell - their primary method of locating prey. Their high metabolic rate (especially in weasels) causes them to be constantly on the move hunting for food. Most mustelines are loners - each individual has its own territory, which is shared only during mating season, and while the young are dependent.
There are other common characteristics in the family. All except otters are able to kill animals much larger than themselves. Two-ounce weasels can kill rabbits and wolverines weighing 50 pounds are known to bring down full-grown reindeer and caribou. They are primarily meat eaters and any mammal can serve as food. To a lesser extent, birds, grubs, eggs, fish, and sea animals are eaten, and sometimes the menu even includes fruit. Some species are very limited in the prey they take; for example, the Black-footed Ferret feeds almost entirely on prairie dogs and gophers, and has become almost extinct as man has killed out these burrowing rodents.
They all share one physical characteristic that has insured a solid and long lasting relationship with man throughout the Northern Hemisphere. Without exception all have pelts that are valuable to the fur industry. Historically, musteline pelts were the most valuable furs of all, although muskrats and beavers probably supplied the greatest number sold annually. The populations of weasels, martens, fishers and especially mink were dropping in the 1800s until man learned to breed them in captivity. Fur from these pen-raised animals is often of better quality than from wild animals, so wild mink populations have increased. Some species of weasels turn white in winter and their fur is called ermine. This was the fur of royalty - 50,000 ermine pelts were used to make the coronation robes worn by George VI in 1937.
Badgers, weasels, and skunks are the only Mustelidae found in Midland County today, but historically black-footed ferrets lived here when prairie dogs were much more numerous. Weasels are very rarely seen in Midland County, but a few records exist in the files of the Midland Naturalists (MIDNATS). Badgers are not numerous and are seldom seen, although MIDNATS often find their burrows. Three species of skunks are found in Midland County. Striped skunks are the most common, while hognosed and spotted skunks are only seen a few times a year. Striped skunks are abundant and are often seen by anyone who spends time outdoors. Skunks live in town and in outlying subdivisions as well as in the open country. Before dumpsters were installed, skunks were prime raiders of garbage cans. A few days ago one spent 30 minutes walking among the flower beds at Sibley as I watched from inside. Unless frightened or disturbed, skunks do not advertise their presence. Their only disagreeable feature is as carriers of rabies. If you meet a skunk, give him a chance to get away. If he stamps his feet, make tracks immediately!