Spotted skunk

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Spotted skunk
Spilogale.jpg
Southern spotted skunk (S. angustifrons), western spotted skunk (S. gracilis) and eastern spotted skunk (S. putorius).
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Carnivora
Family: Mephitidae
Genus: Spilogale
Gray, 1865 [1]
Type species
Mephitis interrupta [2]
Linnaeus, 1758
Spotted Skunk areas.png
Spotted skunk ranges
  Spilogale gracilis Merriam, 1890



The genus Spilogale includes all skunks commonly known as spotted skunks. Currently, there are four accepted extant species: S. gracilis, S. putorius, S. pygmaea, and S. angustifrons. [3] New research, however, proposes that there may be up to seven. [4] [ better source needed ] [5] [6]

Contents

Extant species

In the past, anywhere between two and fourteen species of Spilogale have been recognized, but today most authorities accept a four species model (seen below). A 2021 DNA analysis of 203 specimens from across their known range suggests that there may be as many as seven distinct species in the genus, some cryptic. [4]

ImageScientific nameCommon nameDistribution
Spilogale gracilis.jpg Spilogale gracilis Merriam, 1890
 Western spotted skunk western United States, northern Mexico, and southwestern British Columbia
Spilogale putorius.jpg Spilogale putorius (Linnaeus, 1758)
 Eastern spotted skunk north-central to south-central, and southeastern United States (to Ohio River); and in small areas of Canada (southeast Manitoba, northwest Ontario) and Mexico (northeast near Gulf coast)
Spilogale pygmaea Thomas, 1898
 Pygmy spotted skunk Pacific coast of Mexico
Southern spotted skunk.jpg Spilogale angustifrons Howell, 1902 Southern spotted skunk Mexico, Guatemala, Honduras, El Salvador, Nicaragua, Costa Rica and Belize

Description

Mammalogists consider S. gracilis and S. putorius different species because of differences in reproductive patterns, reproductive morphology, and chromosomal variation. [7] However, interbreeding has never been disproved. [7] The name Spilogale comes from the Greek word spilo, which means "spotted", and gale, which means "weasel". Putorius is the Latin word for "fetid odor". Gracilis is the Latin word for "slender". Several other names attributed to S. putorius include: civet cat, polecat, hydrophobian skunk, phoby skunk, phoby cat, tree skunk, weasel skunk, black marten, little spotted skunk, four-lined skunk, four-striped skunk, and sachet kitty. [8]

Distribution and habitat

Range

The western spotted skunk (Spilogale gracilis) can be found west of the Continental Divide from southern British Columbia to Central America, as well as in some parts of Montana, North Dakota, Wyoming, Colorado, and western Texas. Eastward, its range borders that of the eastern spotted skunk (Spilogale putorius). Spilogale gracilis generally occupies lowland areas but they are sometimes found at higher elevations (2600 m). Although the western spotted skunk is now recognized as S. gracilis, previously, skunks west of the Cascade Crest in British Columbia, Washington, and Oregon were recognized as a distinct subspecies (S. p. latifrons). [9]

Spilogale putorius is found throughout the central and southeastern United States, as well as northeastern Mexico. In Mississippi, S. putorius is found throughout the whole state, except for the northwestern corner by the Mississippi River. In the Great Plains, there has been an observed increase in the geographical range of these skunks, and the cause of this is thought to be a result of an increase in agriculture. This would lead to an increase in mice, which happen to be one of the primary prey for S. putorius. [8]

Habitat

Spilogale usually like to reside in covered thickets, woods, riparian hardwood, shrubbery, and areas that are located near streams. However, S. putorius usually enjoy staying in rocky and woody habitats that have copious amounts of vegetation. These sly creatures prefer to dwell in a den or natural cavities such as stumps or hollow logs. Spotted skunks have been found to adjust well to a wide array of dry prairie ecosystems in shallow dens. They take on a negative relationship with elevation, particularly in regions such as the Northern and Southern Appalachians of the United States. Although they have very effective digging claws, they prefer to occupy dens that are made by gophers, wood rats, pocket gophers, striped skunks, or armadillos. [9] They occupy dens that are positioned to be completely dark inside. Spilogale are very social creatures and frequently share dens with up to seven other skunks. Although skunks often live in this way, maternal dens are not open to non-maternal skunks. [8]

Biology

Reproduction

Around the time of March, the males’ testes begin to enlarge and are most massive by late September. The increase in size is accompanied by a larger testosterone production. Similarly, a female begins to experience an increase in ovarian activity in March. Spilogale begin to mate during March as well. Implantation occurs approximately 14–16 days after mating. For the western spotted skunk, most copulations occur in late September and the beginning of October. [10] Post copulation the zygotes are subject to normal cleavage but stop at the blastocyst stage, where they can remain in the uterus for roughly 6.5 months. After implantation, gestation lasts 30 days and between April and June their offspring are born. [11] Although litter sizes vary considerably, the average litter size is about 5.5 and the gender ratio is 65 M: 35 F. [8]

Growth

The newborn skunks are covered with fine hair that shows the adult color pattern. The eyes open between 30 and 32 days. [12] The kits start solid food at about 42 days and are weaned at about two months. [8] They are full grown and reach adult size at about four months. The males do not help in raising the young.

Defenses

Spotted skunks protect themselves by spraying a strong and unpleasant scent. Two glands on the sides of the anus release the odorous oil through nipples. When threatened, the skunk turns its body into a U-shape with the head and anus facing the attacker. Muscles around the nipples of the scent gland aim them, giving the skunk great accuracy on targets up to 15 feet away. As a warning before spraying, the skunk stamps its front feet, raises its tail, and hisses. They may warn with a unique "hand stand"—the back vertical and the tail waving. [7]

The liquid is secreted via paired anal subcutaneous glands that are connected to the body through striated muscles. The odorous solution is emitted as an atomized spray that is nearly invisible or as streams of larger droplets. [8]

Skunks store about 1 tablespoon (15 g) of the odorous oil and can quickly spray five times in row. It takes about one week to replenish the oil.

The secretion of the spotted skunks differs from that of the striped skunks. The two major thiols of the striped skunks, (E)-2-butene-1-thiol and 3-methyl-1-butanethiol are the major components in the secretion of the spotted skunks along with a third thiol, 2-phenylethanethiol. [13]

Thioacetate derivatives of the three thiols are present in the spray of the striped skunks but not the spotted skunks. They are not as odoriferous as the thiols. Water hydrolysis converts them to the more potent thiols. This chemical conversion may be why pets that have been sprayed by skunks will have a faint "skunky" odor on damp evenings.

Deodorizing

Changing the thiols into compounds that have little or no odor can be done by oxidizing the thiols to sulfonic acids. Hydrogen peroxide and baking soda (sodium bicarbonate) are mild enough to be used on people and animals but changes hair color.

Stronger oxidizing agents, like sodium hypochlorite solutions—liquid laundry bleach—are cheap and effective for deodorizing other materials.

Diet

Skunks are omnivorous and will eat small rodents, fruits, berries, birds, eggs, insects and larvae, lizards, snakes, and carrion. Their diet may vary with the seasons as food availability fluctuates. [8] They have a keen sense of smell that helps them find grubs and other food. Their hearing is acute but they have poor vision.

Life expectancy

Spotted skunks can live 10 years in captivity, but in the wild, about half the skunks die after 1 or 2 years.

Conservation

The eastern spotted skunk, S. putorius, is a conservation concern. Management is hampered by an overall lack of information from surveying. [14] During the 1940s, Spilogale populations seemingly crashed and the species is currently listed by various state agencies as endangered, threatened, or ‘of concern’ across much of its range. [15] The species S. pygmaea is endemic to the Mexican Pacific coast and is currently threatened. [16] The tropical dry forest of western Mexico, where these skunks live, is a highly threatened ecosystem that has been placed on conservation priority. S. pygmaea is also the smallest carnivore native to Mexico as well as one of the smallest worldwide.

Related Research Articles

<span class="mw-page-title-main">Mephitidae</span> Family of mammals

Mephitidae is a family of mammals comprising the skunks and stink badgers. They are noted for the great development of their anal scent glands, which they use to deter predators. Skunks were formerly classified as a subfamily of the Mustelidae ; however, in the 1990s, genetic evidence caused skunks to be treated as a separate family. 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. A 2017 study using retroposon markers indicated that they are most closely related to the Ailuridae and Procyonidae.

<span class="mw-page-title-main">Skunk</span> Common name of mammals in the family Mephitidae

Skunks are mammals in the family Mephitidae. They are known for their ability to spray a liquid with a strong, unpleasant scent from their anal glands. Different species of skunk vary in appearance from black-and-white to brown, cream or ginger colored, but all have warning coloration.

<span class="mw-page-title-main">Thiol</span> Any organic compound having a sulfanyl group (–SH)

In organic chemistry, a thiol, or thiol derivative, is any organosulfur compound of the form R−SH, where R represents an alkyl or other organic substituent. The −SH functional group itself is referred to as either a thiol group or a sulfhydryl group, or a sulfanyl group. Thiols are the sulfur analogue of alcohols, and the word is a blend of "thio-" with "alcohol".

<span class="mw-page-title-main">Island spotted skunk</span> Subspecies of carnivore

The island spotted skunk is an insular endemic carnivore and a subspecies of the western spotted skunk. Little is known about their exact variations from the mainland spotted skunk and variations between locations, resolution of which awaits further genetic and morphologic evaluation. The skunk is only currently found on two islands off the southern coast of California. Its presence has been recorded on San Miguel Island, but it has since been declared extinct in that area. The Channel Island skunk is one of two terrestrial carnivores on the islands, the other being the island fox. It is designated as a species of special concern by the state of California.

<span class="mw-page-title-main">Eastern spotted skunk</span> Species of carnivore

The eastern spotted skunk is a small, relatively slender skunk found in North America, in the central and parts of the southeastern United States and in small areas of Canada and Mexico.

<span class="mw-page-title-main">Hog-nosed skunk</span> Genus of carnivores

The hog-nosed skunks belong to the genus Conepatus and are members of the family Mephitidae (skunks). They are native to the Americas. They have white backs and tails and black underparts.

<span class="mw-page-title-main">Striped skunk</span> Species of mammal

The striped skunk is a skunk of the genus Mephitis that occurs across much of North America, including southern Canada, the United States, and northern Mexico. It is currently listed as least concern by the IUCN on account of its wide range and ability to adapt to human-modified environments.

<span class="mw-page-title-main">Hooded skunk</span> Species of carnivore

The hooded skunk is a species of mammal in the family Mephitidae. Mephītis in Latin means "foul odor", μακρός (makrós) in Greek translates to "long" and οὐρά (ourá) translates to "tail".

<span class="mw-page-title-main">Palawan stink badger</span> Species of carnivore

The Palawan stink badger, pantot or tuldo in the Batak language, is a carnivoran of the western Philippines named for its resemblance to badgers, its powerful smell, and the largest island to which it is native, Palawan. Like all stink badgers, the Palawan stink badger was once thought to share a more recent common ancestor with badgers than with skunks. Recent genetic evidence, however, has led to their re-classification as one of the Mephitidae, the skunk family of mammals. It is the size of a large skunk or small badger, and uses its badger-like body to dig by night for invertebrates in open areas near patches of brush. While it lacks the whitish dorsal patches typical of its closest relatives, predators and hunters generally avoid the powerful noxious chemicals it can spray from the specialized anal glands characteristic of mephitids.

<span class="mw-page-title-main">Western spotted skunk</span> Species of carnivore

The western spotted skunk is a spotted skunk of western North America.

<span class="mw-page-title-main">Butane-1-thiol</span> Chemical compound

Butane-1-thiol, also known as butyl mercaptan, is a volatile, clear to yellowish liquid with a fetid odor, commonly described as "skunk" odor. In fact, 1-butanethiol is structurally similar to several major constituents of a skunk's defensive spray but is not actually present in the spray. The scent of 1-butanethiol is so strong that the human nose can easily detect it in the air at concentrations as low as 10 parts per billion. The threshold level for 1-butanethiol is reported as 1.4 ppb

<span class="mw-page-title-main">Pygmy spotted skunk</span> Species of carnivore

The pygmy spotted skunk is a species of mammal in the family Mephitidae. It is endemic to Mexico.

<span class="mw-page-title-main">American hog-nosed skunk</span> Species of carnivore

The American hog-nosed skunk is a species of hog-nosed skunk from Central and North America, and is one of the largest skunks in the world, growing to lengths of up to 2.7 feet (82 cm). Recent work has concluded the western hog-nosed skunk is the same species, and Conepatus leuconotus is the correct name of the merged populations.

<span class="mw-page-title-main">Southern spotted skunk</span> Species of carnivore

The southern spotted skunk is a species of mammal in the skunk family, (Mephitidae). It ranges from Costa Rica to southern Mexico. At one time this skunk was considered to be a subspecies of the eastern spotted skunk.

References

  1. ↑ Gray, J. E. (1865). "Revision of the genera and species of Mustelidae contained in the British Museum". Proc. Zool. Soc. Lond. 1865: 150.
  2. ↑ Wilson, D. E.; Reeder, D. M., eds. (2005). Mammal Species of the World: A Taxonomic and Geographic Reference (3rd ed.). Johns Hopkins University Press. ISBN   978-0-8018-8221-0. OCLC   62265494.
  3. ↑ Kinlaw, A (1995). "Spilogale putorius". Mammalian Species. 511: 1–7. doi: 10.2307/0.511.1 .
  4. 1 2 "Doubling the number of species of hand-standing spotted skunks".
  5. ↑ Magazine, Smithsonian; Langlois, Jill. "Scientists Identify Seven Species of Spotted Skunks, and They All Do Handstands Before They Spray". Smithsonian Magazine. Retrieved 2021-11-20.
  6. ↑ McDonough, Molly M.; Ferguson, Adam W.; Dowler, Robert C.; Gompper, Matthew E.; Maldonado, Jesús E. (2020-10-25). Phylogenomic systematics of the spotted skunks (Carnivora, Mephitidae, Spilogale): Additional species diversity and Pleistocene climate change as a major driver of diversification (Report). pp. 2020.10.23.353045. doi:10.1101/2020.10.23.353045. S2CID   226229298.
  7. 1 2 3 Kaplan, Joyce (November 1994). "Seasonal Changes in Testicular Function and Seminal Characteristics of the Male Eastern Spotted Skunk (Spilogale putorius ambarvilus)". Journal of Mammalogy. 4 (75): 1013–1020. doi:10.2307/1382484. JSTOR   1382484.
  8. 1 2 3 4 5 6 7 Bullock, Lindsay (December 2008). "Mammals of Mississippi". Department of Wildlife and Fisheries.
  9. 1 2 Verts, B.J.; Carraway, Leslie N.; Kinlaw, Al (June 2001). "Spilogale gracilis". Mammalian Species. 674: 1–10. doi:10.1644/1545-1410(2001)674<0001:SG>2.0.CO;2. S2CID   5999413.
  10. ↑ Kaplan, J.B.; Mead, R. A. (July 1993). "2010 Influence of season on semanal characteristics, testis size and serum testosterone in the western spotted skunk (Spilogale gracilis)". Reproduction. 98 (2): 321–326. doi: 10.1530/jrf.0.0980321 . PMID   8410795.
  11. ↑ Feldhamer, George (2015). Mammalogy Adaptation Diversity Ecology. 2715 North Charles Street, Baltimore, Maryland 21218-4363: Johns Hopkins University Press. p. 229. ISBN   978-1-4214-1588-8.{{cite book}}: CS1 maint: location (link)
  12. ↑ "Eastern Spotted Skunk". The Mammals of Texas - Online Edition.
  13. ↑ Wood, William; Morgan, Christopher G.; Miller, Alison (1991). "Volatile components in defensive spray of the spotted skunk,Spilogale putorius". Journal of Chemical Ecology. 17 (7): 1415–1420. doi:10.1007/BF00983773. PMID   24257801. S2CID   20596160.
  14. ↑ Hackett, H.; et al. (2007). "Detection Rates of Eastern Spotted Skunks (Spilogale Putorius) in Missouri and Arkansas Using Live-capture and Non-invasive Techniques". The American Midland Naturalist. 158 (1): 123–131. doi:10.1674/0003-0031(2007)158[123:DROESS]2.0.CO;2. S2CID   86043600.
  15. ↑ Gompper, Matthew; Hackett, H. Mundy (May 2005). "The long-term, range-wide decline of a once common carnivore: the eastern spotted skunk (Spilogale putorius)". Animal Conservation. 8 (2): 195–201. CiteSeerX   10.1.1.488.4738 . doi:10.1017/S1367943005001964. S2CID   20413459.
  16. ↑ Cantu ́-Salazar, Lisette; Hidalgo-Mihart, Mircea G.; López-González, Carlos A.; González-Romero, Alberto (November 2005). "Diet and food resource use by the pygmy skunk (Spilogale pygmaea) in the tropical dry forest of Chamela, Mexico". Journal of Zoology. 267 (3): 283–289. doi: 10.1017/S0952836905007417 .
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