Eastern Gartersnake (pre-molting/shedding)

Eastern Gartersnake (pre-molting) and fly (Family Muscidae)

The preceding photo shows an Eastern Gartersnake (Thamnophis sirtalis sirtalis) spotted during a photowalk through Huntley Meadows Park on 27 September 2013. Did you notice the fly perching on the snake’s head? When I saw the fly through the camera viewfinder my first thought was, “Either pre-molting snakes are vision-impaired/blind or this fly has a death wish!” Turns out I was partly correct.

Blue-to-gray eyes are usually a sign that the snake is about a day away from molting/shedding its skin. When the eyes are blue-gray their vision is impaired — they can still see some movement and light versus dark, but not much detail. Source Credit: Kevin Munroe, Park Manager, Huntley Meadows Park, Fairfax County Park Authority.

I consulted the BugGuide group on Facebook for help in identifying the fly. Michael Butler identified the fly as a member of the Family Muscidae. Jeff Beane told me the fly was not in danger because garter snakes don’t eat flies! Aaron Belulz and several other folk kindly suggested I had misidentified the snake as a Common Ribbonsnake (Thamnophis sauritus sauritus); after some research and a second-look at my photo set, I realized they were right!

Eastern Gartersnakes can be differentiated from Common Ribbonsnakes by the presence of “dark vertical lines on the supralabial scales.” This key characteristic is shown more clearly in the following photos.

Eastern Gartersnake (pre-molting)

Eastern Gartersnake (pre-molting)

Special thanks to Kevin Munroe as well as all the BugGuide group citizen scientists who helped me with this spotting!

Copyright © 2013 Walter Sanford. All rights reserved.

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2 Responses to “Eastern Gartersnake (pre-molting/shedding)”

  1. Mike Powell Says:

    Wow, a snake with blue eyes is awfully cool, but the fly on its head makes that first photo unique. The images are beautiful and I learned some fascinating new things about snakes

  2. Top 10 Photos of 2013 (plus 10) | walter sanford's photoblog Says:

    […] 27 SEP 2013 | HMP | Eastern Gartersnake (pre-molting/shedding) […]

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