Snake Skin
Park visitor Parissa Salimian, whose springtime photos of a Great Egret appeared here just a few days ago, spotted this shed skin of a gopher snake up on the Western ridge in the park early in July. Although several photographers have taken images of live gopher snakes in the park, Parissa is the first to spot and photograph a snake’s discarded skin.
All snakes discard their skins from time to time. Younger snakes may do it four or more times a year. Older snakes less often, maybe only once a year. The process is called ecdysis, and it’s not confined to herps but occurs also many insects in different forms. With snakes, as they get ready to moult, the outer skin separates from the inner all along the snake’s body. Then the outer skin cracks at the mouth and the snake simply slides out. The videos available on YouTube show the snakes sliding forward out of their old skin, as if the old skin were a thin pipe and they were gliding out of it.
Shedding the old skin replaces a worn outer skin layer with a fresh one. It gets rid of mites, ticks, and other parasites that have burrowed under the scales. Whether snakes have to shed their skin in order to get bigger seems to be disputed in the scientific literature. The skin is quite flexible, as you can see when a snake swallows prey much larger than itself, so it would seem that the snake could put on quite a few pounds in its skin without shedding. But then the younger ones do shed often as they grow, so maybe they need to do that. Herpetologists differ. The newly emerging skin is soft at first but quickly toughens and hardens.
When a snake emerges from its egg, it has all the scales it’s going to have. It adds no scales when it grows new skin, and loses none, but its scales get larger and may change shape. A snake’s scales are an outer layer of skin (epidermis). They’re made out of keratin, the same material as in hair and fingernails. A special transparent scale covers the eyes, in lieu of an eyelid, which it lacks. When it gets ready to moult or shed its skin, the eye scale detaches slightly and the snake’s vision becomes blurry, which tends to make it irritable. A snake’s color and design reside in the base layer of its skin, and not in the scale layer. As Parissa’s photos show, the shed skin is more or less transparent, uniform in tint, and does not show the typical chain-like pattern of the gopher snake in its usual skin-on state. I’m assuming it’s a gopher snake skin because that’s the only kind of snake yet seen in the park, and it’s about the right size. Specialists would be able to examine the shed skin in great detail and confirm (or reject?) the identification.
About snake scales. Another YouTube video. About skins of garden snakes. About the Pacific Gopher Snake.
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Nice find. I’d often found shed gopher snake skins wandering around in the old Berkeley Meadow and on the pre-fenced Albany Plateau / Bulb.
The shed skin ends up inside out, as the snake actually ‘peels’ itself out of the skin from head to tail.
The characteristic pattern of scalation of the head and row counts of body scales, which are retained by the skin, will indicate the species. Also, the shed skin usually retains a ‘shadow’ of the pattern of coloration (e.g., the ‘chain’-like pattern of the gopher snake), and may allow* a species determination without the need to count scales or examine the head scalation. * Weathering / Sun bleaching of a shed skin may make that pattern fade or disappear.