Skunk

Skunks
Striped skunk
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Order:	Carnivora
Suborder:	Caniformia
Superfamily:	Musteloidea
Family:	Mephitidae (in part, see text) Bonaparte, 1845
Genera
Conepatus Mydaus Mephitis (type) Spilogale
Skunk genera ranges

Skunks are mammals known for their ability to spray a liquid with a strong odor. Different species of skunk vary in appearance from black-and-white to brown or cream colored, but all have warning coloration.

Etymology

1630s, squunck, from a southern New England Algonquian language (probably Abenaki) seganku, from Proto-Algonquian */šeka:kwa/, from */šek-/ "to urinate" + */-a:kw/ "fox." As an insult, attested from 1841. Skunk cabbage is attested from 1751; earlier skunkweed (1738).^[1] In 1634, a skunk was described in the Jesuit Relations:

The other is a low animal, about the size of a little dog or cat. I mention it here, not on account of its excellence, but to make of it a symbol of sin. I have seen three or four of them. It has black fur, quite beautiful and shining; and has upon its back two perfectly white stripes, which join near the neck and tail, making an oval which adds greatly to their grace. The tail is bushy and well furnished with hair, like the tail of a Fox; it carries it curled back like that of a Squirrel. It is more white than black; and, at the first glance, you would say, especially when it walks, that it ought to be called Jupiter's little dog. But it is so stinking, and casts so foul an odor, that it is unworthy of being called the dog of Pluto. No sewer ever smelled so bad. I would not have believed it if I had not smelled it myself. Your heart almost fails you when you approach the animal; two have been killed in our court, and several days afterward there was such a dreadful odor throughout our house that we could not endure it. I believe the sin smelled by Saint Catherine de Sienne must have had the same vile odor.^[2]

Physical description

Skunk species vary in size from about 15.6 to 37 in (40 to 94 cm) long and in weight from about 1.1 lb (0.50 kg) (spotted skunks) to 18 lb (8.2 kg) (hog-nosed skunks). They have moderately elongated bodies with relatively short, well-muscled legs and long front claws for digging.

Although the most common fur color is black and white, some skunks are brown or grey and a few are cream-colored. All skunks are striped, even from birth. They may have a single thick stripe across back and tail, two thinner stripes, or a series of white spots and broken stripes (in the case of the spotted skunk). Some also have stripes on their legs.

Diet

Skunks are omnivorous, eating both plant and animal material and changing their diets as the seasons change. They eat insects and larvae, earthworms, grubs, small rodents, lizards, salamanders, frogs, snakes, birds, moles and eggs. They also commonly eat berries, roots, leaves, grasses, fungi and nuts.

In settled areas, skunks also seek garbage left by humans. Less often, skunks may be found acting as scavengers, eating bird and rodent carcasses left by cats or other animals. Pet owners, particularly those of cats, may experience a skunk finding its way into a garage or basement where pet food is kept. Skunks commonly dig holes in lawns in search of grubs and worms.

Skunks are one of the primary predators of the honeybee, relying on their thick fur to protect them from stings. The skunk scratches at the front of the beehive and eats the guard bees that come out to investigate. Mother skunks are known to teach this behavior to their young.

Behavior

Skunks are crepuscular and solitary animals when not breeding, though in the colder parts of their range, they may gather in communal dens for warmth. During the day, they shelter in burrows which they can dig with their powerful front claws. Males and females occupy overlapping home ranges through the greater part of the year, typically 2 to 4 km² (0.77 to 1.54 sq mi) for females and up to 20 km² (7.7 sq mi) for males.

Skunks are not true hibernators in the winter, but do den up for extended periods of time. However, they remain generally inactive and feed rarely, going through a dormant stage. Over winter, multiple females (as many as 12) huddle together; males often den alone. Often, the same winter den is repeatedly used.

Although they have excellent senses of smell and hearing, they have poor vision, being unable to see objects more than about 3 m (10 ft) away, making them vulnerable to death by road traffic. They are short-lived; their lifespan in the wild can reach seven years, with most living only up to a year.^[3][4] In captivity, they may live for up to 10 years.^[3][4]

Reproduction

A striped skunk kit

Skunks mate in early spring and are polygynous, meaning that successful males mate with more than one female. Before giving birth (usually in May), the female excavates a den to house her litter of four to seven kits. They are placental, with a gestation period of about 66 days.^[5]

When born, skunk kits are blind, deaf, and covered in a soft layer of fur. About three weeks after birth, their eyes open. The kits are weaned about two months after birth, but generally stay with their mother until they are ready to mate, at about one year of age.

The mother is protective of her kits, spraying at any sign of danger. The male plays no part in raising the young.

Anal scent glands

Skunks are notorious for their anal scent glands, which they can use as a defensive weapon. They are similar to, though much more developed than, the glands found in species of the family Mustelidae. Skunks have two glands, one on each side of the anus. These glands produce a mixture of sulfur-containing chemicals such as thiols, traditionally called mercaptans, which have a highly offensive smell. The odor of the fluid is strong enough to ward off bears and other potential attackers and can be difficult to remove from clothing. Muscles located next to the scent glands allow them to spray with a high degree of accuracy, as far as 3 m (10 ft). The smell aside, the spray can cause irritation and even temporary blindness, and is sufficiently powerful to be detected by a human nose up to a mile (1 ¹⁄₂ km) down wind. Their chemical defense is effective, as illustrated by this extract from Charles Darwin's Voyage of the Beagle:

We saw also a couple of Zorrillos, or skunks—odious animals, which are far from uncommon. In general appearance, the Zorrillo resembles a polecat, but it is rather larger and much thicker in proportion. Conscious of its power, it roams by day about the open plain, and fears neither dog nor man. If a dog is urged to the attack, its courage is instantly checked by a few drops of the fetid oil, which brings on violent sickness and running at the nose. Whatever is once polluted by it, is for ever useless. Azara says the smell can be perceived at a league distant; more than once, when entering the harbour of Monte Video, the wind being off shore, we have perceived the odour on board the Beagle. Certain it is, that every animal most willingly makes room for the Zorrillo.^[6]

Western spotted skunk, also called a zorrillo, which means "little fox" in Spanish

Skunks are reluctant to use this weapon, as they carry just enough of the chemical for five or six uses – about 15 cc – and require some ten days to produce another supply.^[7] Their bold black and white coloration make their appearance memorable. It is to a skunk's advantage to warn possible predators off without expending scent: black and white aposematic warning coloration aside, threatened skunks will go through an elaborate routine of hisses, foot-stamping, and tail-high deimatic or threat postures before resorting to spraying. Skunks usually do not spray other skunks, except among males in the mating season. If they fight over den space in autumn, they do so with teeth and claws.

Most predators of the Americas, such as wolves, foxes and badgers, seldom attack skunks, presumably out of fear of being sprayed. The exceptions are dogs, reckless predators whose attacks fail once they are sprayed, and the great horned owl.^[8] It is the skunk's only regular predator.^[9] In one case, the remains of 57 striped skunks were found in a single owl nest.^[10]

Skunks are common in suburban areas. Frequent encounters with dogs and other domestic animals, and the release of the odor when a skunk is run over, have led to many myths about the removal of skunk odor. Due to the chemical composition of the spray, most of these household remedies are ineffective,^[11] except for remedies able to break down thiols.

Skunk spray is composed mainly of three low-molecular-weight thiol compounds, (E)-2-butene-1-thiol, 3-methyl-1-butanethiol, and 2-quinolinemethanethiol, as well as acetate thioesters of these.^{[12][13][14][15][16]} These compounds are detectable by the human nose at concentrations of only 10 parts per billion.^[17][18]

One of the most commonly held beliefs is that a pet that has been sprayed should be bathed in tomato juice in order to neutralize the smell. This, however, can require extremely large amounts of tomato juice and is only marginally effective. The Humane Society of the United States recommends using a mixture of dilute hydrogen peroxide (3%), baking soda, and dishwashing liquid.^[19]

Bites

It is rare for a healthy skunk to bite a human. While a domesticated skunk with its scent glands removed may defend itself by biting, there are few recorded incidents. The most prevalent cause of skunks biting humans is the rabies virus. The Centers for Disease Control (CDC) recorded 1,494 cases of rabies in skunks in the United States for the year 2006 — about 21.5% of reported cases in all species.^[20][21] Skunks trail raccoons as vectors of rabies, although this varies regionally (in the United States, raccoons dominate along the Atlantic coast and eastern Gulf of Mexico, skunks throughout the Midwest and down to the western Gulf, and in California).

Domestication

A domesticated skunk

Mephitis mephitis, the striped skunk species, is the most social skunk and the one most commonly domesticated. When a skunk is kept as a pet, its scent glands are often surgically removed. Skunks can legally be kept as pets in the UK, but the Animal Welfare Act 2006^[22] has made it illegal to remove their scent glands. The keeping of skunks as pets is illegal in most US states.^[23]

Classification

Skunks, together with stink badgers, belong to the skunk family, the "Mephitidae",^[24][25] which is in the order Carnivora. There are twelve species of mephitids, in four genera: Conepatus (hog-nosed skunks, four species); Mephitis (the hooded and striped skunks, two species); Mydaus (stink badgers, two species); and Spilogale (spotted skunks, four species). The two stink badgers in the genus Mydaus inhabit Indonesia and the Philippines; the other members of the family inhabit the Americas, ranging from Canada to central South America. All other mephitids are extinct, known through fossils, including those from Eurasia.

Skunks were formerly classified as a subfamily of the Mustelidae (the weasel family); however, recent genetic evidence has caused skunks to be treated as a separate family.^[25] Similarly, the stink badgers had been classified with badgers, but genetic evidence shows they share a more recent common ancestor with skunks, so they are now included in the skunk family.^[26][27] In alphabetical order, the living skunk species are:^[28]

A hooded skunk skeleton on display at the Museum of Osteology

• Family Mephitidae
  • Genus: Conepatus
    • Conepatus chinga – Molina's hog-nosed skunk
    • Conepatus humboldtii – Humboldt's hog-nosed skunk
    • Conepatus leuconotus – American hog-nosed skunk
    • Conepatus semistriatus – striped hog-nosed skunk
  • Genus: Mephitis
    • Mephitis macroura – hooded skunk
    • Mephitis mephitis – striped skunk
  • Genus: Mydaus
    • Mydaus javanensis – Indonesian or Sunda stink badger (Teledu)
    • Mydaus marchei – Palawan stink badger
  • Genus: Spilogale
    • Spilogale angustifrons – southern spotted skunk
    • Spilogale gracilis – western spotted skunk
    • Spilogale putorius – eastern spotted skunk
    • Spilogale pygmaea – pygmy spotted skunk

See also

• List of fictional skunks
• Skunk oil

References

External links

• Skunk at DMOZ
• Skunks and the management of skunk damage
• Encyclopedia of Life