Copperhead or Not ?

September 10, 2016

Nature Notes by Bill Dunson

On  a recent bike ride along the New River Trail in VA  I was more or less in auto-pilot and was paying less attention to my surroundings than I should have.  My biking companion Mason suddenly shouted that he had run over a copperhead !  I was shocked that I had been so careless to have not noticed the rare snake and also doubted that it was really a copperhead.  Humans have a very strained relationship with snakes and often misidentify them.  But to my surprise and delight, it was indeed a copperhead.   Against the gravel background of the trail the copperhead stood out in stark relief.  When I moved it off into the adjacent leaves it blended in magnificently.  Aside from a very beautiful camouflage pattern, copperheads have an elliptical pupil and a distinctive pit organ between the eye and nose.  This is a most remarkable sensory structure that allows for the snake to detect infrared radiation and to distinguish a tiny difference in temperature between an object and the background.  This seemed to be a female snake that was gravid, so I am hoping she did not suffer serious damage from being hit by the bike tire.

Although copperheads are venomous, they are not generally lethal.  But what are some other local snakes that might be confused with copperheads?  Probably the number one common snake that is often misidentified is the northern water snake, which is blotched, but has a very different look or “giz” and lacks the vertical pupil and pit.

The milk snake is also blotched but is much thinner and has a very different head shape.  Some other blotched snakes are the juvenile pilot black snake and the black racer (not shown).   Both have a much thinner shape than young copperheads and lack a yellow tail tip.

So why do people have so much trouble distinguishing the dangerous copperhead from a number of common non-venomous snakes?  Partly it is a matter of unfamiliarity and inattention to detail.  The differences are quite clear and perhaps many people simply see any snake as a danger and kill it.  This seems to be a learned response since babies show no fear of snakes.  Let’s try to teach our kids and grandkids to show more respect for a beautiful and rarely seen member of our biosphere.

Bill Dunson

About Bill Dunson

Bill Dunson, born in rural Georgia, skipped 12th grade and went directly to Yale. Bill subsequent-ly received a PhD in Zoology from the University of Michigan, studying softshell turtles. Bill is Professor Emeritus of Pennsylvania State University thanks to a career spent entirely at that institution, teaching and doing research on the physio-logical ecology and ecotoxiciology of reptiles, amphibians and fish. Always curious about nature, Bill has dedicated his life to learning and sharing his knowledge with others. He has served on many advisory boards here in Southwest Florida to preserve the water that gives life to our region.

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