Striped Skunk

Mephitis mephitis

Summary 3

The striped skunk (Mephitis mephitis) is an omnivorous mammal of the skunk family Mephitidae. Found north of Mexico, it is one of the best-known mammals in Canada and the United States.

Behaviour 4

Mephitis mephitis relies primarily on visual displays to ward off predators or unwanted visitors and may resort to a chemical discharge if not left alone. Although they are usually silent, an individual can produce a wide variety of sounds from low growls to birdlike chirps. Little is known about their perception; however, an individual may react to auditory or visual cues at close range. Deprivation in visual, acoustic and even olfactory sensation has been considered a potential result of their defensive capabilities in additional to their passivity.

Communication Channels: visual ; tactile ; acoustic ; chemical

Perception Channels: visual ; tactile ; acoustic ; chemical

Communication and perception 5

Striped skunks use scent marking to communicate presence and reproductive state to other skunks. They also communicate visually, by raising their fur and changing posture. Skunks have a good sense of hearing, but their vision is poor. They are mostly silent, but do make a variety of sounds such as churring, hisses, and screams.

Communication Channels: visual ; tactile ; acoustic ; chemical

Other Communication Modes: scent marks

Perception Channels: visual ; acoustic

Conservation actions 6

Conservation Actions

Given the ecological and economic importance of this species, there is a need to better understand microhabitat factors that are associated with occurrence of the taxon (Baldwin et al., 2004).

Cyclicity 7

Comments: Mostly crepuscular or nocturnal, sometimes active during daytime. May be dormant during extended periods of cold snowy weather; males more likely to be active in winter.

Description 8

The Striped Skunk is the most common skunk in North America, yet most of what we know about it comes from studies of captive individuals. Like all skunks, it has a superb defense system, the ability to spray a foul-smelling fluid from two glands near the base of its tail. Skunk musk is oily and difficult to remove. If sprayed in the eyes, it causes intense pain and temporary blindness. Skunk kittens can spray when they are only eight days old, long before they can aim, a skill they exhibit only after their eyes open at about 24 days. Skunks attempt to give a warning before they spray: both Hooded and Striped skunks stamp their front feet before turning around and spraying. Like all skunks, Striped Skunks are nocturnal and eat a variable diet, mostly of insects, but also including small mammals, carrion, and some vegetation.

Links:
Mammal Species of the World
Click here for The American Society of Mammalogists species account

Distribution 9

Striped skunks (Mephitis mephitis) have a range spanning most of North America. From east to west, they reach from the Atlantic to the Pacific Ocean, covering most of the continental United States and southern regions of Canada. They also range to the south over a portion of northern Mexico.

Biogeographic Regions: nearctic (Native )

Distribution 10

Global Range: Throughout much of North America, from northern Baja California, northern Durango, northern Tamaulipas, and Florida to central Canada (southwestern Northwest Territories, Hudson Bay, southern Quebec).

Ecology 11

Home range up to several hundred ha; males tend to wander more than do females. Population density may fluctuate greatly. Several individuals, mainly females, may share winter den

Economic importance for humans: negative 12

Striped skunks sometimes eat crops and raid chicken pens, though this is rare. They are one of the primary carriers of sylvatic rabies and thus can be very dangerous to pets and humans. They can also cause some damage when building their burrows.

Negative Impacts: injures humans (carries human disease); causes or carries domestic animal disease

Economic importance for humans: positive 13

Striped skunks, because of their diet, often eliminate insect and rodent pests that cause destruction of crops. In the past, skunk furs were of great importance to the fur industry, but skunk fur value has declined along with the industry. Skunks are also kept as pets, though this is illegal in most states because of their role in rabies transmission.

Positive Impacts: pet trade ; body parts are source of valuable material; controls pest population

Economic uses 14

Comments: Large numbers of pelts taken in some areas, but value relatively low (pelt yielded average of about $1.60 in Ok in early 1980s (Caire et al. 1989). Can do considerable damage to poultry. Major carrier and reservoir of rabies (though most skunks are not rabid).

Ecosystem roles 15

Skunks help to control insect populations.

Food habits 16

Striped skunks are true omnivores. A skunk's diet depends on what is available in its foraging territory. They eat many things including insecta, small mammalia (such as baby Peromyscus maniculatus and baby Peromyscus leucopus), carrion, Aves, crustaceans (such as Orconectes propinquus), fruits, grasses, leaves, buds, grains, and nuts.

Insects make up approximately 70% of their diet. Striped skunks often attack the nests of colonial insects, such as Apoidea and Formicidae. When attacking a bee hive, they wait for the angry bees to emerge from the hive, then bat them out of the air and eat them. Striped skunks also eat large numbers of Orthoptera and Coleoptera.

Animal Foods: mammals; fish; carrion ; insects; terrestrial non-insect arthropods; terrestrial worms; aquatic crustaceans

Plant Foods: leaves; seeds, grains, and nuts; fruit

Geographic range 17

Striped skunks are native only to the Nearctic region. They are found throughout much of North America, ranging from central Canada, throughout the United States, and south into northern Mexico.

Biogeographic Regions: nearctic (Native )

Habitat 18

Mephitis mephitis is commonly found in a variety of habitats including woodlands, forests, wooded ravines and grassy plains. Over time, however, they have become more prominent in areas of extreme cultivation as well as in suburban neighborhoods. Other habitats may include scrubland, riparian areas and urban environments. On average, M. mephitis is found at elevations from sea level to 1,800 m, but have been documented as high as 4,200 m.

Range elevation: sea level to 4,200 m.

Average elevation: sea level to 1,800 m.

Habitat Regions: temperate ; terrestrial

Terrestrial Biomes: savanna or grassland ; chaparral ; forest ; scrub forest

Other Habitat Features: urban ; suburban ; agricultural ; riparian

Habitat 19

Comments: Prefers semi-open country with woodland and meadows interspersed, brushy areas, bottomland woods. Frequently found in suburban areas. Dens often under rocks, log, or building. May excavate burrow or use burrow abandoned by other mammal.

Habitat 20

Striped skunks prefer open areas with a mixture of habitats such as woods, grasslands, and farms. They are found in all but the most arid habitat types. They usually live within two miles of a water source. They are frequently found in suburban areas where buildings provide them with burrows.

Habitat Regions: temperate

Terrestrial Biomes: chaparral ; forest ; rainforest ; scrub forest

Other Habitat Features: urban ; suburban ; agricultural

Habitat and ecology 21

Habitat and Ecology

There is no single well-defined land type that can be classed as skunk range. They live in a variety of habitats: woods, plains, and desert areas but prefer open or forest-edge zones (Walker, 1964). Striped skunks are most abundant on agricultural lands where there is an ample supply of food and cover (Hamilton and Whitaker, 1979). They also adapt to life in urban areas under houses and garages (Rue, 1981; Rosatte, 1986; Larivière et al., 1999). They have been known to inhabit poorly drained marsh areas (Mutch, 1977). Although recorded from 4,200 m skunks usually are found from sea level to 1,800 m (Rue, 1981). Frequently found in suburban areas. Striped skunks are opportunistic omnivorous predatory feeders (Carr, 1974). Their diet varies depending on season and geographic location. In most areas, they feed extensively on insects (usually grasshoppers and beetles) associated with grassland areas (as opposed to forests). However, when insects are not available (early spring, late fall), their diet shifts to small mammals, birds, or vegetation (Verts, 1967).

Systems

  • Terrestrial

Known prey organisms 22

Mephitis mephitis preys on:
Pseudacris triseriata
Plethodon cinereus
Chelydra serpentina
Trachemys scripta
Eumeces fasciatus
Thamnophis butleri
Diadophis punctatus
Lampropeltis triangulum
Branta canadensis
Anas fulvigula
Anas americana
Fulica americana
Ceryle alcyon
Dendroica petechia
Carpodacus mexicanus
Spermophilus lateralis
Peromyscus gossypinus
Clethrionomys californicus

This list may not be complete but is based on published studies.

Life expectancy 23

Mephitis mephitis has a high mortality rate and usually does not survive its first year due to severe weather conditions and infectious disease. Past their first year, they can live up to seven years in the wild and up to 10 years in captivity. Other factors contributing to mortality include predation and parasitism as well as risk from human road systems and a vulnerability to hunting.

Range lifespan
Status: wild:
7.0 (high) years.

Range lifespan
Status: captivity:
10 (high) years.

Average lifespan
Status: wild:
less than one years.

Average lifespan
Status: wild:
6.0 years.

Average lifespan
Status: captivity:
10.0 years.

Lifespan/longevity 24

Up to 90% of skunks die in their first winter. In the wild skunks may live to be 2 to 3 years old. In captivity they have been known to survive for up to 15 years

Range lifespan
Status: wild:
3 (high) years.

Range lifespan
Status: captivity:
15 (high) years.

Typical lifespan
Status: wild:
1 (high) years.

Average lifespan
Status: wild:
<1 years.

Average lifespan
Status: captivity:
10.0 years.

Management 25

Management Requirements: See Conover (1990) for information on the use of emetine dihydrochloride to reduce predation on chicken eggs. See Bickle et al. (1991) for information on the use of hormone implants to limit populations through control fertility; this method could be useful in urban/suburban situations.

Migration 26

Non-Migrant: Yes. At least some populations of this species do not make significant seasonal migrations. Juvenile dispersal is not considered a migration.

Locally Migrant: Yes. At least some populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).

Locally Migrant: No. No populations of this species make annual migrations of over 200 km.

Morphology 27

Striped skunks are easily distinguishable by their coloration pattern. With overall black pelage, they have a thin, white stripe along the center-top of their snout and forehead as well as a prominent white marking on their nape. While pattern varies greatly across individuals, the white marking on their nape typically runs along the dorsum, splitting into a thick, V-shape as it approaches their rump. Additionally, there are frequently white hairs on the edges of their bushy, black tail. With their small, triangular-shaped heads, striped skunks have short ears and black eyes that lack a nictitating membrane. Their maw holds 34 total teeth, with the following dental formula: I 3/3, C 1/1, P 3/3, M 1/2. Their legs are stout, with five-toed plantigrade feet and long foreclaws for digging.

They display minor sexual dimorphism, the males are slightly larger than the females. While most sources agree that M. mephitis is about the size of domestic cats, there is some discrepancy in their measurements. Their total length has been documented many times and estimates range from 465 to 815 mm. Their tail length differs slightly less; with measurements ranging 170 to 400 mm. Discrepancies are not as severe in the hindfoot measurements, with a range of 55 to 85 mm.

Measurements of body mass in M. mephitis also show a large range, between 0.7 to 6.3 kg. However, during periods of wintering, a reduction in body mass can result in losses of up to 47.7% in males and 50.1% in females, mostly due to fat metabolism. These overall differences could be an indication that M. mephitis differs in size across geographic ranges in the same way it differs in pelage patterns.

Range mass: 0.7 to 6.3 kg.

Range length: 465 to 815 mm.

Other Physical Features: endothermic ; homoiothermic; bilateral symmetry

Sexual Dimorphism: male larger

National distribution 28

Canada
Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

United States
Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

Physical description 29

Striped skunks are easily recognized by their unique colors and pattern. Their fur is black with a white stripe that begins as a triangular shape on the top of the head and splits into two stripes that travel down the sides of the back. These two stripes come together again near the base of the tail. They also have a white stripe running from their nose between their eyes and ending on their forehead. Striped skunks are about the size of small house cats, with a small head, small ears, short legs, and a long, fluffy tail. Claws are longer on the front feet to aid in digging. Skunks are from 575 to 800 mm in body length and have tails that are from 173 to 307 mm in length.

Range mass: 1200 to 5300 g.

Range length: 575 to 800 mm.

Sexual Dimorphism: sexes alike

Population 30

Population

Density estimates for striped skunk populations ranged from 0.7 to 18.5/km2 but most were 1.8 to 4.8/km2 (Allen and Shapton, 1942; Bailey, 1971; Bennitt and Nagel, 1937; Burt, 1946; Jones, 1939; Stout and Sonenshine, 1974; Verts, 1967). Density levels reported fluctuated widely between years, possibly in response to outbreaks of diseases (Allen and Shapton, 1942; Brown and Yeager, 1943; Verts, 1967). Skunk populations seemingly have high recruitment and turnover rates because 50 to 71% of striped skunks do not attain an age of 1 year (Bailey, 1971; Casey and Webster, 1975; Verts, 1967). Due to removal of top predators (Crooks and Soulé, 1999; Rogers and Caro, 1998; Soulé et al., 1988), altered land use (Dijak and Thompson, 2000; Donovan et al. 1997; Oehler and Litvaitis, 1996), reduced harvest of skunks (Hamilton and Vangilder, 1992), and perhaps other factors, populations of M. mephitis, have increased in abundance in many regions during recent years (Andren, 1995; Kuehl and Clark, 2002).

Population Trend
Stable

Predation 31

Striped skunks have perhaps the most widely known defense system of any mammal, the scent-spraying mechanism. Striped skunks usually do not spray unless their life is in danger. When faced with danger, striped skunks arch their back and put up their tail and hair. If they feel that their life is in danger, they will bend into a U-shape with both head and rear-end facing the enemy. They then squirt out two streams of fluid from their rear-end that can travel up to 3 meters. The spray often causes nausea and burns the eyes and nasal cavities of the unfortunate target. Skunks advertise their noxious characteristic with their bright coloration, a phenomenon called aposematism. When an animal is sprayed by this brightly colored animal it will quickly learn to associate the skunk's appearance with their unpleasant experience and avoid skunks in the future. Because of their offensive odor, skunks are rarely preyed on by mammalian predators, which typically have an excellent sense of smell. Instead they are eaten primarily by large birds, such as Bubo virginianus and Buteo jamaicensis.

Known Predators:

  • great horned owls (Bubo_virginianus)
  • red-tailed hawks (Buteo_jamaicensis)

Anti-predator Adaptations: aposematic

Reproduction 32

Under normal circumstances, female striped skunks only reproduce once a year, although males will reproduce with multiple females. Beyond fertilization, a female no longer associates with males and in fact will become aggressive towards them through vocalizing, stamping their feet and fighting if necessary.

Mating System: polygynous

Males approach from behind and begin by smelling and licking the female’s vulva. Seeking to mount, the male moves by the female's side where he proceeds to seize her nape. Females often resist, not becoming receptive until estrous, in which case they will usually take a submissive posture. Once successfully mounted, the male continues his copulatory thrusts. Copulation typically ends one minute after the male's acceptance.

Breeding usually occurs sometime between February and April. However, a secondary period can take place in May if the first litter is lost or in other cases, such as pseudopregnancy. Gestation lasts about 59 to 77 days, beginning with a period of delayed implantation that can last up to 19 days. Mephitis mephitis can produce a litter that ranges from 2 to 10 individuals, with individual masses of 32 to 35 g.

Breeding interval: Female striped skunks breed once a year under normal circumstances.

Breeding season: Breeding occurs from February to April, or during May under extenuating circumstances.

Range number of offspring: 2.0 to 10.0.

Average number of offspring: 4.0 to 7.0.

Range gestation period: 59 to 77 days.

Range weaning age: 6.0 to 7.0 weeks.

Range time to independence: 0.5 to 1.0 years.

Average age at sexual or reproductive maturity (female): 10 months.

Average age at sexual or reproductive maturity (male): 10 months.

Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization ; viviparous ; delayed implantation

Average birth mass: 33.5 g.

Average number of offspring: 5.

Average age at sexual or reproductive maturity (male)
Sex: male:
335 days.

Average age at sexual or reproductive maturity (female)
Sex: female:
335 days.

Although they are altricial with sparse pelage at birth, younglings have discernable patterns prior to birth. The younglings do not open their eyes until about three weeks of age and are typically weaned at six to seven weeks. It is at this time they learn to forage and hunt by following their mother in a single file line during her outings. Younglings rely on the protection of their mother, during this time she will display extremely defensive behavior. Male younglings become independent by July or August, while the female younglings may remain with their mother until the following spring. Both male and female younglings become sexually mature by the end of the first year, around 10 months of age on average.

Parental Investment: altricial ; pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Female); pre-weaning/fledging (Provisioning: Female, Protecting: Female); pre-independence (Protecting: Female); post-independence association with parents

Reproduction 33

Males usually live alone, except for a few days during the breeding season.

Mating System: polygynous

Striped skunks breed from mid-February until mid-March. The mother carries the babies for 59 to 77 days. From 1 to 10 helpless young are born. They are blind, deaf, and hairless but are capable of spraying skunk must as early as 8 days old. Their eyes open at 24 days old and their ears open soon after that. They are cared for in the den by their mother for two months, after which they are weaned. Young may stay with their mother for up to a year after reaching their adult size.

Breeding season: February and March

Range number of offspring: 1.0 to 10.0.

Range gestation period: 77 (high) days.

Average weaning age: 2 months.

Average age at sexual or reproductive maturity (female): 10 months.

Average age at sexual or reproductive maturity (male): 10 months.

Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); fertilization ; viviparous ; delayed implantation

Average birth mass: 33.5 g.

Average number of offspring: 5.

Average age at sexual or reproductive maturity (male)
Sex: male:
335 days.

Average age at sexual or reproductive maturity (female)
Sex: female:
335 days.

Female striped skunks nurture their young inside their bodies before they are born and then provide them with milk afterward. Male skunks provide no parental care.

Parental Investment: altricial ; pre-hatching/birth (Provisioning: Female, Protecting: Female); pre-weaning/fledging (Provisioning: Female, Protecting: Female)

Size in north america 34

Sexual Dimorphism: Males are 15% larger than females, but females have longer tails.

Length:
Range: 575-800 mm

Weight:
Range: 1,200-5,300 g

Taxonomy 35

Comments: Based on patterns of mtDNA variation in Mustelidae, Dragoo and Honeycut (1997) recommended that skunks (Mehitis, Conepatus, Spilogale) and the Oriental stink badger (MYDAUS) be separated as a distinct family (Mephitidae). Wozencraft (in Wilson and Reeder 2005) recognized the family Mephitidae.

Threats 36

Major Threats

Striped skunks (Mephitis mephitis) are vulnerable to a variety of mortality agents such as predation, disease, environmental conditions (e.g., severe winter or drought), chemicals, and anthropogenic activities (Gehrt, 2005; Hansen et al., 2004; Rosatte and Larivière, 2003). Another limiting factor in skunk populations are diseases such as rabies and the resultant control programs (Sikes, 1970). Terrestrial rabies apparently was the case for skunks in Illinois, where population fluctuations are closely tied to rabies outbreaks (Verts, 1967). Striped skunk pelts were considered valuable commodities in the fur trade in the first half of the 20th century, but their value and the number of skunks harvested for fur declined dramatically in the 1950's and 1960's as fashions shifted away from long-haired furs (Verts, 1967). Striped skunks may be harvested in most areas of the United States and Canada. In some states, such as Florida, skunks may be taken only in season, but most states allow harvests year-round (Rosatte, 1987).

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