Thursday, October 26, 2023

The "Have You Ever Seen A Skunk Without Stripes?" Story

It was an ordinary day.  Reading that skunks can lose their stripes...and now we might know why.  Although skunks have long been known for their distinctive coats of black with a white stripe down the middle of their back, a new study recently examined why some skunks are evolving to have different fur patterns.  Interesting!!  Oh, the things that are done in the name of science.  Where did the skunks white line go?  A fellow named Ted Stankowich is an evolutionary behavioral ecologist at California State University and he studies "aposematism," or warning colorations, like the bright colors that adorn coral snakes and poison dart frogs.  Well, seems that he also is studying the striped skunk which is native to much of North America and sports some of the most recognizable colorations on the planet;  jet-black fur and white racing stripes that run from head to tail.  Evidently the strips are a warning signal to a predator that they have a strong, stinky defense.  But Mr. Stankowich and others have noticed something curious about striped skunks.  The animals possess different patterns, from a small patch of white on their heads to bold white stripes that merge into a cape-like pattern.  A skunk can also be an all-white or all-black animal.   This may seem odd, since "the more consistent a signal on an animal may be, the more the predator gets one image in their head and knowns when to avoid the animal."  But, a recent study might explain these varying patterns and how we humans may be influencing them.  As far as the skunk goes...their scent glands can squirt sulfuric secretions into a predator's eye, yielding the predator helpless at times.  The skunks foes generally include mountain lions, coyotes, jaguars and bobcats which are either hungry enough to risk the spray or who come upon a skunk with markings that doesn't  accurately convey the threat posed.  Recently, Mr. Stankowich photographed 749 striped skunk skins in museums across the continent and recorded factors such as stripe length and pattern symmetry, and then compared them with other variables such as the environments the animals and other potential predators inhabited.  In an area with  strong predation risk you get a much more consistent, traditional black animal with two long stripes on the body, but as the risk declines, you get more variation in a skunk's stripes.  It is suspected that when there aren't as many predators in waiting, there's less selection for strong warning stripes to get passed on through the generations.  Thus, as generations of skunks continue, you get wider and wider variations in stripe patterns.  Studies like this gives you the idea that we have this mosaic of selection pressures over North America.  And...since people have hunted and outright eliminated predators in the United States, from mountain lions to wolves, it seems logical to ask if humans are to blame for skunks starting to look less like a skunk by losing the white stripes on their backs.  Makes sense to me!  So, the skunk is a pretty smart character, being they know that by eliminating the strips on their back, we might not know they are a skunk...and therefore possibly leave them alone!  Pretty smart animal...if that is truly the reason for the loss of the white strips on their back.  It was another extraordinary day in the life of an ordinary guy.

No comments:

Post a Comment