Thursday, October 20, 2011

Can You Actually Get Stabbed by a Snake?

A Rainbow Snake captured in a trap in southwestern Georgia
            Yesterday, an article caught my attention because the subject was a mysterious creature that is rarely seen or photographed. The Rainbow Snake, Farancia erytrogramma, is a large species highly-associated with wetlands. It is one of the most visually-striking species of wildlife that can be found in the southeastern United States. Covered by dark and glossy scales, bright red lines run alongside the body. Underneath, the animal is yellow.

       Possessing such bright colors, you might expect that Rainbow Snakes are hard to miss. But, they are rarely seen. Some say we don’t see these snakes often because they’re so aquatic, spending much of their time completely submerged.  There is likely some truth to this, even when Rainbow Snakes poke their head out of the water to breathe, they may still be concealed by vegetation or root masses. Other people say that we don’t see the Rainbow Snake often because their populations are declining and they are truly rare.

       This is a tough sell. When an animal is hard to find, it’s exceedingly difficult to know how their populations are doing. It is just impossible to know how many animals there are at any given time. But, the hypothesis of declining populations may have some merit. One scientific article from 1945 reported that Rainbow Snakes were among the most commonly observed snakes in the marshes of Kent County, Virginia. That’s a hard fact to fathom for many herpetologists I know, most of whom have never seen a single Rainbow Snake in the wild (myself included).

       Around 1950, a population of Rainbow Snakes was found in Glades County, Florida, near Lake Okeechobee. Since the animals were distinct from Rainbow Snakes elsewhere, they were considered a separate subspecies. No other animals from this area were ever found again. After many years of fruitless searches, the United States Fish and Wildlife Service recently decided the subspecies was extinct.

       If Rainbow Snakes are declining, what is causing their populations to crash? The answer may relate to their habitat and food preferences. This species happens to be relatively picky about both. Rainbow Snakes prefer flowing streams and rivers with clear water. So, pollution and damming may ruin their habitats. Interestingly, adult Rainbow Snakes are thought to eat almost exclusively eels, Anguilla rostrata. Eels have their own problems, and no eels means no Rainbow Snakes.

            But, I’m going way off topic from what I originally intended to write about. Rainbow Snakes (and their close relative, the Mudsnakes) are just fascinating animals. I recently submitted a short note describing some aspects of their natural history, I’ll write more about them here if the note gets published. In any case, back to the topic at hand.

       The article I saw yesterday, which describes a Rainbow Snake sighting in Virginia, contains this quote, “The raimbow (sic) snake and it's (sic) close relative, the mud snake, will thrash about…and actually try to stab the handler with its tail that ends in a somewhat sharp point.”

       That sounds fairly terrifying. And, I think it’s safe to say that it kind of implies that Rainbow Snakes can, well…stab a person.

       They can’t.

       Rainbow Snakes have a scale on the tip of their tail that is hardened, compared to the other scales on their body.  They sometimes do exhibit the very intriguing behavior of pressing their tail against your skin. But, it’s a gently prodding touch, not anything close to what would be required to break your skin (a side note: whenever I have handled Rainbow or Mudsnakes they have been very docile and don't mind my touch; they certainly did not "thrash about").

       It’s actually a mystery as to why Rainbow Snakes press their tail against people handling them. It seems to be much too gentle of a touch to deter predators. Some have suggested that Rainbow Snakes may use their specialized tail tip to help handle their slippery eel prey. In any case, it is likely that this behavior has led to the origin of a couple entertaining snake myths, including that of the stinging snake and the hoop snake. I’ll tackle these myths in a future column, this one accidentally went too long.

       Have you ever seen a Rainbow Snake? I would be very interested to hear of the experience below (especially if it stabbed you).

Much of what I write is based on my experience in the field, however I also rely on the research of others, citations of some relevant scientific articles are below.

Richmond, N. (1945). The Habits of the Rainbow Snake in Virginia Copeia, 1945 (1) DOI: 10.2307/1438169

Neill, W. (1964). Taxonomy, Natural History, and Zoogeography of the Rainbow Snake, Farancia erytrogramma (Palisot de Beauvois) American Midland Naturalist, 71 (2) DOI: 10.2307/2423288

Durso, A.M., J.D. Willson, & C.T. Winne (2011). Needles in haystacks: estimating detection probability and occupancy of rare and cryptic snakes Biological Conservation, 144, 1508-1515

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