Ecdysis is the shedding our molting of scales in reptiles. Snake scales are extensions of the epidermis or outer layer of skin. When a snake is ready to molt it stops eating and hides or moves to a safe place. The inner surface of the old outer skin liquefies and separates from the new inner skin. The old skin breaks near the mouth and the snake then wriggles out, often turning the skin inside out like a sock. The complete outer layer is shed in one layer or piece when the snake molts leaving a perfect imprint of the snake’s scale pattern. Snakes molt several times a year, more often when young. Why molt? The process replaces old, worn out skin, gets rid of mites, ticks and other skin parasites and allows growth. If the snake skin is reasonably intact, the identity of the snake can be determined from the discarded skin.
Last week while walking in our North Pasture (near Lookout CA in Modoc County)I saw a partial snake skin sticking out of a hole in the ground. I carefully pulled the skin out of the hole. To my delight it was a perfectly intact specimen. Of course, the challenge was to identify the species of snake that shed the skin. First I measured the length – 39″ or 3 feet 3 inches.
The skin when found was turned inside out as can be seen in the picture of the head. Snakes have a transparent scale (brille) over each eye. As I am not in the habit of grabbing live snakes to check out their scales or eyes, it was interesting to finally get a good view of brille.
The first question was: Is this a viper (poisonous) or colubrid (non-poisonous) snake? Colubrid snakes have a double row of sub-caudal (under the tail) scales while vipers have a single row of sub-caudal scales. Non-poisonous.
Next whether the dorsal (on the back) scales are keeled (have a ridge) or unkeeled (smooth) must be determined. This snake had smooth scales.
I did not use the ventral scales in identifying this snake. As seen in the photograph, the ventral (on the bottom) scales look different from the dorsal scales.
Is the anal plate divided or not? This snake skin had a divided (two sections) anal plate.
Using these few clues (colubrid, smooth scales, divided anal plate) it was easy to narrow the possibilities to about ten groups of snakes. Then out came the guide book and I checked the range and length of each potential group. The list quickly narrowed to the racer and whipsnake group.
The pattern of head scales further confirmed that I was heading in the correct direction.
Finally I counted the number of dorsal scales at midbody and found 17. The number of dorsal scales at various points along the body is characteristic for different species. The center frontal scale is bell-shaped. Both the number of dorsal scales at midbody and the bell-shaped center frontal scale fit the description of a striped whipsnake (Masticophis taeniatus). My snake skin was from a striped whipsnake.
The habitat of a striped whipsnake is open, brushy country, desert scrub, sagebrush flats and mixed woodlands often along the edges of rivers or ponds – check. The range maps indicate this species lives in Modoc County CA – check. And adult striped whipsnakes reach a length of 24 to 67 inches – check.
Striped whipsnakes are very fast moving and do not give you much time to observe them in the wild, however they are easy enough to identify in the few seconds before they disappear into the grass and brush. Their long, thin bodies are olive, black, brown, or dark grey on top and cream on the underside, sometimes becoming yellow or pink closer to the tail. There is a greyish white or cream stripe down each side. On first glance they resemble garter snakes. However, garter snakes have a stripe down the center of the back which the striped whipsnake does not.
A synonym for M taeniatus is Coluber taeniatus. Coluber may be the currently accepted genus designation, but that is not agreed upon by all taxonomists.
No matter what the scientific name for the striped whipsnake, it was fun to identify the origin of the snake skin I found.