Mustelidae

WEASEL FAMILY. More than 60 species of carnivorous mammals, distributed throughout the world, are included in the weasel family Mustelidae. They are placed in five major groups, or subfamilies: true weasels, which include ermine, minks, ferrets, martens, and wolverines; honey badgers; badgers; skunks; and otters.
Among the true weasels are a number of well-known animals. The common, or long-tailed, weasel (Mustela frenata) is a slender animal with a body length of up to 12 inches (30 centimeters). The long-tailed weasel feeds constantly, eating mice, rats, and also poultry, and for this reason is regarded as a pest in some areas. The smallest member of the weasel family is the least weasel (M. nivalis). This is the tiniest carnivore in the world (the length of its head and body is less than 10.2 inches, or 26 centimeters), and it resembles the long-tailed weasel in many respects. Mice are its primary food source. A closely related species is the ermine, or stoat (M. erminea). It is a nocturnal predator that eats small mammals, insects, and bird eggs. During winter it stores its dead prey underground. Ermine are one of the most highly prized mammals in the fur trade and are found over much of the colder portions of North America, Europe, and Asia, including Siberia and parts of the Himalayas.
Other true Old World weasels with similar habits and appearances are also valued in the fur trade. The European polecat (M. putorius) grows a fur known as fitch. The fur of the Siberian weasel (M. sibirica) is called kolinsky. The furs of the European mink (M. lutreola) and American mink (M. vison) are also popular. The minks live along streams, rivers, and lakes and are good swimmers. Their food consists of animal prey found in or around water.
Martens (genus Martes), also true weasels, comprise several species of forest-dwelling predators of the northern regions of North America, Europe, and Asia. The fisher of the United States and the Eurasian furbearer known as the sable (Martes zibellina) are members of this group.
The wolverine (Gulo gulo) is a large terrestrial carnivore that exhibits remarkable ferocity even when faced with animals much larger than itself, including humans. Its diet is varied and includes large mammals, such as reindeer, that it sometimes kills but more frequently scavenges.
The honey badger, or ratel (Mellivora capensis), is assigned a subfamily of its own within the weasel family. It is a robust, powerful creature of Africa and the Middle East. It will attack and eat both large and small animals and is known to tear into bee hives in order to eat the honey as well as the bees themselves. Its thick skin makes it almost invulnerable to the bees' stings.
Within the badger subfamily are the Old World badger (Meles meles) and American badger (Taxidea taxus), both heavy, short-limbed, burrowing species. They possess powerful jaws and large, heavy claws on their forefeet that they use to construct underground homes and escape routes. They are nocturnal and feed on small animals and plant material. The American badger is noted for eating large numbers of rodents, many of which it digs from the ground.
The skunks are best known for a foul-smelling spray that they discharge, when threatened, from musk glands in the posterior part of their bodies. They generally exhibit characteristic warning behavior, such as foot stamping and (in spotted skunks) "hand-standing" on the front feet. If the threat continues, the animal turns its hindquarters toward the target and ejects a fine spray of yellow, malodorous liquid as far as 12 feet (3.7 meters). Most skunks are omnivorous, consuming invertebrates, small vertebrates, and some plant material.
Individuals in the otter subfamily of weasels remain in the vicinity of water throughout their lives, sometimes making burrows into the banks of rivers or lakes. They are expert swimmers, and much of their diet consists of fishes or invertebrates taken directly from the water. Otters are extremely sociable animals. Several members of a family may hunt or play together. The North American river otter (Lutra canadensis) occurs throughout most of the United States and Canada, but its numbers have been reduced considerably in many regions as a result of excessive trapping and habitat alteration. The sea otter (Enhydra lutris) is the only living marine species in the weasel family. Its range includes coastal regions of the Bering Sea and the Pacific Ocean of North America. Most of a sea otter's time is spent in the ocean, within sight of shore, feeding on marine animals such as fish, mollusks, and crustaceans.
Most members of the weasel family have long, slender bodies (though some may be more stockily built), and males are larger than females. Both sexes of some species may defend their territory aggressively. Musk glands are present in the posterior regions of most species and are extremely developed in some.
Coloring of most animals of the weasel family is generally solid shades of brown, but a variety of other colors are also found. One striking exception is the ermine. In the summer it is dark brown above and white beneath, but in winter it develops long, thick white fur all over, except for a black-tipped tail. In northern regions the common weasels and least weasels are also brownish during summer then turn white during winter. In the natural state, minks are dark brown in color. However, experimental breeding at mink farms has produced animals with coats of black, white, and gray. Badgers have grayish coats and a black-and-white striped pattern on their faces. The skunks have black-and-white patterns of stripes or spots that may warn enemies from a distance of their unpleasant defense.
Members of the weasel family are found on every continent except Australia and Antarctica, and at least one member can be found on most major land masses. The European polecat was introduced into New Zealand years ago and has become established in some regions. Several species or genera within the weasel family have extensive geographic ranges that span as many as three continents. For example, the least weasel ranges throughout Europe to China and Japan, and from Siberia to Alaska, Canada, and the northern United States. (Some scientists, however, consider those in the Western Hemisphere to be a different species.) The long-tailed weasel is widespread in the Western Hemisphere, ranging from southern Canada to South America. Collectively, the ranges of the European and American minks cover most of North America and the northern portion of Eurasia. All species of skunks are confined to the Western Hemisphere; the striped skunk (Mephitis mephitis) ranges across most of Canada and the United States into Mexico. The geographic ranges of the eight species of river otters encompass most of the Americas, Eurasia, and Africa as well as Indochina and Japan.
The wolverine is found today primarily in the most northern parts of North America, Europe, and Asia, but in earlier times its range extended into central Europe and into the midwestern United States. Although it is not considered a major furbearer compared to some members of the weasel family, it has still been hunted in large numbers because of its reputation for killing livestock, eating animals captured in the lines of fur trappers, and breaking into the cabins of hunters. The black-footed ferret (Mustela nigripes), a close relative of the European polecat, is native to the North American prairies but is now an endangered species because of the destruction in many areas of its main food source, prairie dogs.
The members of the weasel family occupy highly diverse ecological habitats ranging from tropical forests to the Arctic tundra. Terrestrial, arboreal, burrowing, and aquatic or semi-aquatic species are found. The only marine species in recent times, other than the sea otter, was the now extinct sea mink (Mustela macrodon) that lived on the Atlantic coasts of North America during the 19th century.
A few species have highly specialized hunting and feeding habits. The sea otter is one of the few animals that uses a tool. While swimming on its back, the sea otter will place a rock on its belly and break a shell open by hammering it against the rock. The honey badger and the honey guide, a bird that finds beehives, exhibit an unusual symbiosis. The honey guide utters a call to indicate that it has located a hive, and the honey badger then follows it through the forest. Once the hive is reached, the mammal tears it apart, and both animals feed on the hive's contents.
Each year after a male and female weasel mate, a single litter of two to eight young is produced, depending on the species. The gestation period is normally one to two months. However, several months may elapse between fertilization and birth in many species due to a delay in the implantation of the fertilized egg in the female. Because of this phenomenon, some species, such as the otters, may remain pregnant for more than a year. The young are nursed by the mother for about two months.
The fur trade has been responsible for the destruction of large numbers of the weasel family. Ermine, mink, and sable produce some of the highest priced furs. Wolverines have been used to make parkas, and the fur of badgers was once used to make shaving brushes. In China the tail hairs of some species have been used to make artists' brushes. Now, because of the sharp reduction in the numbers of these animals, strict international regulations have been instituted by government conservation agencies. Thus, though many of the species in the weasel family that are sought for their fur are trapped in the wild, mink farms (also called ranches) and sable farms supply a high proportion of today's furs. In fact, almost all mink, fitch, and sable furs today come from farm-raised animals; fur from wild-caught individuals is estimated to have constituted less than 10 percent of the world's fur trade in 1990, compared to more than 30 percent in the early 1970s.

From Compton's Living Encyclopedia