Spilogale graciliswestern spotted skunk

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Geographic Range

S. gracilis inhabits the western half of the United States. Some taxonomists call the western spotted skunk a subspecies of S. gracilis and others consider it a separate species.(Whitaker 1980)

Habitat

The western spotted skunk prefers rocky bluffs and brush-bordered canyon stream beds. They make dens in rocky outcrops or hollow logs in the wild; however, they often live in close association with people, frequently nesting in rock fences or even attics (Davis and Schmidley 1994).

Physical Description

The western spotted skunk looks much like the eastern spotted skunk except that the white areas are more extensive. Both are relatively small and slender. They are black with a white spot on their forehead and in front of each ear. They have a pair of dorsolateral white stripes on the anterior portion of their bodies beginning at the back of their head, a pair of lateral stripes confluent with the spots in front of the skunk's ears, and a ventrolateral pair which begins just behind the forelegs. These cut off at mid-body and the posterior portion of the skunk's body has two interrupted white bands, a white spot on each side of the rump and two more at the base of the tail. The underside of the tail is white for nearly half its length and the tip is extensively white. The ears are short and low on the sides of the head. They have five toes on each foot but the claws on the front feet are more than twice as long as those on the back feet, sharp, and recurved. Males average 423mm in length (134 of that being tail) and 565 g in weight. Females average 360 mm (129 tail) and 368 g (Davis and Schmidley 1994).

Reproduction

The testes of adult and young males begin enlarging in March, producing sperm in May, and reach their peak by September. Females come into heat around in September and breeding begins. Most are bred by October when the formation of sperm is halted and the testes begin to regress again. The blastula stage of the embryo is free floating in the uterus for the first 180-200 days before implanting. Gestation usually lasts 210-230 days and litters ranging from 2-5 young are born in late April or May (Davis and Schmidley 1994). Baby skunks are called kits (Savage 1999). Young females become sexually mature at about 4 or 5 months of age and the cycle begins again (Davis and Schmidley 1994).

  • Key Reproductive Features
  • gonochoric/gonochoristic/dioecious (sexes separate)
  • sexual

Behavior

Skunks are nocturnal. They are shortsighted and self-absorbed (Savage 1999). They usually range within a half a mile of their den (Skunks). S. gracilis is also very mobile - it is an agile climber and an excellent digger (Davis and Schmidley 1994). Mate selection is done by females. When the kits are born, they remain in a "family" with their mother until they are mature (Savage 1999), often following her in a single file line as they travel. Skunks are not true hibernators but females often den up in groups of up to 20 or so and sleep for weeks at a time during the winter. Males stay alone and move about all winter (Skunks). This skunk, like all skunks, possesses two scent glands located on each side of its anus that spray a very foul smelling musk as an anti-predator defense. The skunk precedes its defense by raising its tail, stomping, hissing, charging, scratching, and aiming (Savage 1999). These defensive warning signs can also be seen in the play of young skunks. The skunk generally aims for the attacker's eyes, temporarily blinding it as well as assaulting its olfaction with the yellowish colored butyl mercaptan containing liquid which can be ejected up to 10 feet (Skunks). Mercaptans, or thiols, are organic compounds that contain sulfur. Skunks, too, seem to be bothered by their smell and will not spray around their dens or each other, even when they are fighting. The "nipples" through which they emit these chemicals can modify and direct the intensity of the spray (Wheeler 1998). However, their hind feet have to be set on something for them to spray. Young skunks don't have as much spray and their scent is weaker. Their feces also have a strong odor (Skunks).

Communication and Perception

Food Habits

Skunks are omnivores. They enjoy eggs (wild or domestic, especially turkey eggs), young rabbits (Davis and Schmidley 1994), fruit and berries (Skunks), mice, voles, roots, and even arthropods such as grasshoppers (Savage 1999), and scorpions (Davis and Schmidley 1994).

Economic Importance for Humans: Positive

Skunks help keep down populations of animals such as rodents and grasshoppers which can be harmful to a farmer's crops (Savage 1999). They also eat scorpions, which may be useful to people by keeping down the population of this poisonous arthropod, especially since these skunk prefers to live near developed areas (Davis and Schmidley 1994). People have also begun descenting skunks and keeping them as pets because they are quite friendly and can be kitty litter trained (Skunks).

Economic Importance for Humans: Negative

The skunk in general may be seen as a pest because of its affinity for making dens in human property combined with the foul smell it is capable of emitting. The fear that skunks carry rabies has shown to be no more worrisome than any other wild animal (Savage 1999). It is also known to nest in attics and steal turkey eggs from farmers (Davis and Schmidley 1994).

Conservation Status

Recently described as a separate species from the eastern spotted skunk because of differences in color pattern, cranial features, reproductive physiology, and breeding season; the western spotted skunk is neither endangered nor threatened. It is adapting readily to the new sources of food and habitats provided by civilization (Davis and Schmidley 1994).

Other Comments

One remedy for skunk odor is 1 quart 3% hydrogen peroxide (from the pharmacy),1/4 cup baking soda, and 1 teaspoon liquid soap. Wash and rinse keeping away from eyes, nose, and mouth (Skunks). Another source suggests watered down bleach (Wheeler 1998).

Contributors

Katrina Hakkinen (author), Southwestern University, Stephanie Fabritius (editor), Southwestern University.

Glossary

Nearctic

living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.

World Map

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

chemical

uses smells or other chemicals to communicate

endothermic

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

tactile

uses touch to communicate

References

Anonymous, September 1997. Countryside and Small Stock Journal., 81(5): 61-66.

Davis, W., D. Schmidly. 1994. The Mammals of Texas. Austin, TX: Texas Parks and Wildlife Nongame and Urban Program.

Savage, C. July 1999. Debunking the skunk. Canadian Geographic, 119(5): 20-22.

Wheeler, M. June 1998. Discover, 19(6): 44-48.

Whitaker, Jr., J. 1980. The Audubon Society Field Guide to North American Mammals. New York: Alfred A. Knopf.