Game & Fish explain stinky science behind Wyoming's three skunk species - Casper, WY Oil City News
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Game & Fish explain stinky science behind Wyoming’s three skunk species

A spotted skunk performs a handstand. (United States Fish & Wildlife Service photo via Nebraska Game & Parks)

CASPER, Wyo. — Wyoming Game & Fish Statewide Nongame Bird and Mammal Program Supervisor Zack Walker explained on Thursday, July 23 that Wyoming has three species of skunk.

Those are the striped skunk, the Easter spotted skunk and the Western spotted skunk. All three species spray, according to Walker.

“Skunks are small, but they can be smelly,” he said. “The reason skunks smell bad is because of a gland under their tail that produces and sprays their stink.”

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“The stinky spray is an oily liquid primarily made up of a substance called thiols, with a sulfur component that is the earmark of the signature skunk odor. A skunk’s smell is hard to get rid of because compounds within the skunk’s oil interact with water, reactivating the odor, so it can bring up the smell again even if you think it’s gone.”

Walker says that skunks have the ability to spray thiols from birth.  

“The spray is a defense mechanism – so they will spray if they are surprised or feel threatened,” he added. “Skunks will often give warning signs that they might spray, like stamping their feet or flicking their tail. Spotted skunks can even do a handstand while spraying!”

Game & Fish says that the “plains subspecies of Eastern Spotted Skunk (Spilogale putorius interrupta) is petitioned for listing under the United States Endangered Species Act (ESA).”

“The species as a whole is assigned a range of state conservation ranks by the Wyoming Natural Diversity Database (WYNDD) due to uncertainty concerning the proportion of its Wyoming range that is occupied, the resulting impact of this on state abundance estimates, and, to a lesser extent, due to uncertainty about extrinsic stressors and population trends in the state,” Game & Fish adds.

While Western spotted skunk and Eastern spotted skunk are “commonly recognized” as distinct species in the United States, Game & Fish says that some authors have questioned whether they are distinct species.

“Others maintain that they are distinct based on morphologic characteristics, differences in breeding strategy, and molecular data,” Game & Fish add.

Spotted skunks are the smallest species of skunk in North America. They are “easily distinguished by their distinct pelage consisting of many white patches on a black background, compared to the large, white stripes of the more widespread and common striped skunk (Mephitis mephitis),” the department says.

“It is very difficult to tell Eastern and Western Spotted Skunk from each other in the field, particularly based on visual sighting rather than a captured animal,” Game & Fish add. “The primary (and somewhat subjective) differentiating characteristic is that Eastern Spotted Skunk has less extensive white markings than Western Spotted Skunk.”

“In particular, Eastern Spotted Skunk has a mostly black tail with a small white tip, while Western Spotted Skunk has extensive white on the end and underside of tail. Pending development of suitable genetic differentiation, the two species are ultimately distinguished by chromosome number (Eastern has 64 chromosomes; Western has 60 chromosomes) and reproductive strategy (Eastern has a gestation period of 50–65 days with no delayed implantation; Western has a gestation period of 210–250 days and exhibits delayed implantation).”

Eastern spotted skunk can possibly be found in the eastern basins of Wyoming, east of the Laramie and Bighorn Mountain ranges “but this
is largely conjecture based on relatively limited occurrences.”

“Initially more restricted to the southeastern states, agricultural development may have facilitated the expansion of Eastern Spotted Skunk into the Great Plains early in the 1900s,” Game & Fish continue. “Population declines have been reported in the Great Plains…but there does not appear to have been a concurrent contraction or shift in the species’ range nationally or in Wyoming.”

Game & Fish say that Eastern spotted skunk tend to avoid open areas and prefer dense vegetative cover.

“It is often associated with dry, brushy, and rocky woodlands with thick understory such as second-growth deciduous forest, dense palmetto thickets, and oak-hickory forests,” the department says. “Eastern Spotted Skunk uses dens, which can be virtually any natural cavity (e.g., talus or rock piles, hollow logs, stumps), burrow (self-excavated or from
other small mammals), or man-made structure (e.g., haystacks, wood piles, farm buildings) as long as they provide shelter from the elements, protection from predators, and minimal human disturbance.”

In Wyoming, the Eastern spotted skunk may prefer “wooded areas with
rock outcrops and moderate to low overstory canopy cover” based on the limited available information.

“Across its range, Eastern Spotted Skunk is omnivorous, but it may focus on particular dietary components depending on location and season,” Game & Fish add. “The species is largely insectivorous where insects are consistently plentiful, but shifts to other prey sources (e.g., small mammals, birds and bird eggs, carrion, and plant material) during seasons when insects are not available.”

Game & Fish provide further information about both Eastern spotted skunk and Western spotted skunk.