Posts Tagged ‘hypothesis that cat diseases depress skunk populations’

The Mysterious Decline of the Eastern Spotted Skunk (Spilogale putorius)

September 6, 2016

I was delivering newspapers on Sand Bar Ferry Road in Augusta, Georgia on the only occasion I’ve ever seen a live spotted skunk.  In the 26 years since that 4 am encounter, I’ve driven by maybe 2 road-killed specimens on I-20 between Augusta and Atlanta.  The eastern spotted skunk is a rare animal, though it has a wide range from southern Canada to Florida and west to the prairie states.  But it has not always been as uncommon as it is today.  Like other small carnivore/omnivore species such as opossum, raccoon, and fox; it adapted well to European modification of the wilderness.  They benefitted from the elimination of larger predators, and the creation of edge habitat between forest and farmland.  Formerly, spotted skunks could often be found in burrows under barns and hay stacks where they hunted their favorite prey–mice.  Until the 1940s trappers killed over 100,000 annually in some states.  However, within a 3-5 year period spotted skunk populations declined by 90% and have never recovered.  Scientists don’t know why.

Spotted skunk demonstrating its warning handstand.

Spotted skunk doing a handstand.  If you see one doing this, flee the area…it’s about to spray.

Scientists suspect many causes in the spotted skunk population decline but none fit the timing or align with the known facts.  Modernization of farming techniques is 1 suspected cause.  Modern farmers expand cultivated fields and eliminate natural border areas, and they consolidate barns.  This does infringe on spotted skunk habitat.  However, agricultural modernization has been a long term process, and the decline of the spotted skunk occurred rapidly.  Pesticide use is another suspect because insects are an important item in the spotted skunk’s diet.  But widespread use of pesticides began after the decline of spotted skunk populations.  Scientists looking at the data can’t “fully implicate” over trapping as the culprit in the decline.  They also can’t find a definite correlation with any diseases.  Most small animals respond cyclically to disease outbreaks, but eventually inherited immunity among some individuals allows their numbers to bounce back.  Spotted skunk numbers never recovered from their sudden decline.  The mink enteritis virus spread throughout mink farms in the 1940s, so this is 1 possible disease that may have devastated spotted skunk populations.  Still, they should have recovered by now.

I propose diseases spread by feral or domestic cats may play a role in keeping spotted skunk populations depressed.  Skunks and house cats are known to interact in a friendly manner.  They even play together, and skunks will often feed on the food left outside for cats.  Because cats are so numerous, they are more likely to have stronger immune systems and can survive diseases that the far less common skunks are susceptible to.

Video of a cat playing with 2 wild baby skunks.  House cats and skunks get along well together.  I hypothesize diseases carried by cats depress skunk numbers.

The spotted skunk is listed as a species of conservation concern.  Unfortunately, it receives little attention because it is…just a skunk.  This is a shame.  The spotted skunk is a neat little mammal, usually weighing less than 3 pounds.  It is more acrobatic than its larger, more common cousin, the striped skunk (Mephitis mephitis).  It can climb trees and when it is threatened it stands on its front paws and can accurately spray from 10 feet away.  This species is little studied.  One of the few studies of spotted skunks (in the Oachita Mountain National Forest, Arkansas) determined they prefer closed canopy forests with dense undergrowth.  The dense undergrowth keeps them hidden from their most dangerous predator–the great horned owl.  Ironically, the habitat they prefer is the opposite of what wildlife managers are aiming for here.  Wildlife managers are using prescribed fire to create open short leaf pine forests with grassy understories where spotted skunks would be vulnerable to predation.

The spotted skunk has a long evolutionary history in North America.  It likely descended from a late Pliocene ancestor known as Spilogale rexroadi over 2 million years ago.  Fossil remains of Spilogale putorius dating to the Pleistocene have been excavated all over North America including a specimen recovered from Ladds Mountain in north Georgia.  I hope this species can survive in the future from the scourge of the cat diseases or whatever problem(s) ails it.


Gompper, Matthew; K. Hackett

“The Long Term, Range-Wide Decline of a Once Common Carnivore: the Eastern Spotted Skunk (Spilogale putorius)”

Animal Conservation May 2005

Lesmeister, Damon: Matthew Gompper, Joshua Millspagh

“Summer Resting and Den Site Selection by Eastern Spotted Skunks (Spilogale putorius) in Arkansas”

Journal of Mammalogy 2008