The harmless broad-banded water snake is a beautiful snake, with broad bands of olive, black, dark brown, and reddish brown patches separated by yellowish interstices. Those colors practically scream “copperhead” to the uninitiated, and even give many, if not most experienced herpers a start for a second or two when they happen upon one in the wild. It seems likely that this similarity is another example of Batesian mimicry (Wickler, 1968) that benefits the water snake by causing it to be mistaken for a copperhead, and thus to be given a wider berth — sparing its life — than would otherwise be the case. [...]
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The specimen in Walter’s possession seems clearly to be a ratsnake (all North American colubrids that were once included in the genus Elaphe could rightly be classified as ratsnakes, though the designation was not very precise), but how do we know that? it was not a Texas ratsnake (previously classified as Elaphe obsoleta lindheimeri, now as Pantherophis obsoletus) because it displayed — albeit imperfectly — a spearpoint marking on its dorsal crown, which character is wholly lacking in the Texas rat snake juvenile. Under the older, now-defunct nomenclature it would have been more accurate to classify it as Texas cornsnake (Elaphe guttata), which according to some (Conant & Collins, 1998; Tennant, 1998) was then represented in Texas by but one subspecies, the Great Plains ratsnake (Elaphe guttata emoryi), and to others (Werler & Dixon, 2000) by three separate subspecies, including — besides the Great Plains ratsnake — the type species known simply as the cornsnake (Elaphe guttata guttata) and the southwestern ratsnake (Elaphe guttata meahllmorum). [...] So, you’ve found what you think is a snake and you want to know what kind it is. But what distinguishes snakes from lizards, skinks, and other, similar-appearing reptiles? If you are not completely sure it is (or isn’t) a snake, the first order of business is to learn what makes snakes unique among their reptilian brethren. Taxonomically, snakes are vertebrate reptilian animals in the order Squamata and the suborder Serpentes. That is, snakes and other reptiles are members of the… [...] Snakes are reptiles in the suborder Serpentes. They have elongated bodies without legs, eyelids, and external ears, and are uniformly carnivorous. They can be found on every continent except Antarctica, Ireland, New Zealand, and a number of islands in the Atlantic and central Pacific oceans. A total of fifteen families, 456 genera and more than 2,900 species are recognized worldwide. The following index is confined to the families, genera, and species found in North America. [...] On Labor Day, 5 September 2011, while I was doing research in Garland, Texas, my cell phone rang. On answering, Darryl Archer, of Manvel, Texas (a town of 7,000, some 24 miles due south of Houston), spoke the following words to me: “Hi, Mr. Cates… my wife just got bit by a snake in our back yard, and I’m hoping you can help me identify what bit her.” [...] As a result, we can expect snakes to show up in places where they are seldom seen. It isn’t so much that we will see more snakes, because snake populations, like those of rodents, drop during a drought. But if this drought is like most that we’ve had in the past, we will be seeing more snakes than normal, and we’ll see them in places they aren’t normally found. [...] This is a western cottonmouth (Agkistrodon piscivorus leucostoma), also known as a water moccasin. The copperhead (Agkistrodon contortrix) has pinkish copper-colored markings — emphasis on the pinkish background — and the face does not have the conspicuous black eye stripe, from the eye back to the mouthline, edged in white, as shown in your specimen. [...] The thumbnail to its right shows the unsheathed fang next to a measuring bar with 1/8th inch (3.2 mm) graduations. From that image we can safely conclude the fangs of this specimen would be able to penetrate to about 5/8th inch (16 mm) or more into the flesh of its prey or that of a perceived threat… [...] Like all things in life, fortunes sometimes favor the spider-eating-snake, and sometimes they favor the snake-eating-spider (and, just in case you hadn’t heard of a snake-eating-spider before, well… read on). [...] Notice the somber hues on the body of this snake. Olive gray along its spine and dorsum, two pale stripes on the side, the scales under the chin momentarily yellowish, but the yellow does not continue onto the belly (as would be the case with a yellow-bellied racer), but instead turning to a pale, mottled blue-gray just beyond the neck. This darker, blue gray marks most of the remaining belly, but not at the boundary of the belly and the sides, where the belly coloration grades to a pale white. [...] |
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