Rattlesnakes on the “Great Rattlesnake Highway” II: The Western Diamond-Backed Rattlesnake

 

(This article was written by both Clint and Michael)

Clint: First rattlesnake of 2017

An unusually bright and warm February sky saw two winter-weary herpers atop a rocky outcrop at roadside south of the Red River.  It was late afternoon, and the beaming sun, with not so much as a solitary cloud to hinder it, had raised the temperature to over ninety degrees Fahrenheit.  It was a bit of false spring advertisement, a drastic warm-up that would be followed by a rainy bout of cold weather that reminded us all that winter isn’t over quite yet.  But the day showed no sign of the latter at this moment, as Michael and I slowly made our way up the incline to the hilltop.

A thick knee-high layer of thorn studded brush tattooed our limbs with red stinging slashes as we finished our ascent.  This was a little known personal hot spot of mine, one I had stumbled on completely by accident a decade ago.  It was a relatively innocuous looking place, not that much unlike the rest of the surrounding landscape: rocky red dirt broken by uprising heaves of sandstone and limestone, the porous, erosive nature of which had carved an elaborate network of ever widening trenches and gullies between boulders.  The top of the hill flattened out into a wide, flat mesa crowned with post oak, mesquite, and prickly pear, but all except its eastern edge lay out of our reach behind a rusty barbed wire fence held up by dried mesquite branches.  It was the kind of background one might expect to see in a cowboy painting hanging on the smoke-yellowed wall of a west Texas cafe.  But we had not come all this way just to look at scenery.  This was the site of what had once been the winter hibernaculum of a fairly large number of western diamond-backed rattlesnakes, and over the past ten years I had used it to scratch that reptilian itch that always seems to get downright unbearable in the normally herp-less void just before the arrival of spring.  By February I can hardly stand it, and so with the first sunny, fairly warm day I make the journey up to this clandestine spot to get what is usually my first glimpse of scales for the new year.

The den is not what it used to be, unfortunately.  The first year I discovered it, my presence alerted a nearby homeowner who resided in the valley less than a hundred yards from the hillside.  As he made his way up he saw my wife and I standing like apostles among a congregation of some thirty plus sunning rattlesnakes, one of which was coiled in the typical defensive posture in front of my camera, the sound of its protest cutting the otherwise still air.  After a brief introduction, the man mentioned that he killed rattlesnakes every spring and fall in his yard, and now knew why.  Although I did my best to serve as a defense attorney for the snakes, I could tell my words were falling on deaf ears.  No explanation as to their natural role or desire to be left alone was going to persuade him otherwise.  “I’d rather be overrun with rats than rattlesnakes!” he exclaimed, and I began to worry whether I had unintentionally sealed the doom of this particular population.

The next year’s visit gave me the answer I had been dreading.  As I pulled up to the site my heart sank.  Someone had burned away all of the brush that had concealed the main den entrance, which was a series of tunnels beneath a monolithic sandstone block roughly the size of a small car.  Even more disheartening were the dried, fire-mummified carcasses of several large rattlesnakes, their charred trunks forever frozen in the grim agony of having been burned alive.  But a glimmer of light remained.  As I walked among the senseless carnage a sound caught my ear.  It was very faint at first, a muffled buzzing like an underground nest of bees.  I knelt down closer to the rock and sure enough, the startled caudal alarm of several rattlesnakes could be heard somewhere below me, doubtless in response to my vibrating footsteps.  As I broadened my inspection I heard more, beneath other boulders, and at the top, in a channel of eroded red dirt I found three adult diamondbacks, looking winter thin and dark, their violet-black tongues flicking slowly as they sized me up.

Since that day I have almost never failed to see (or at least hear) a few rattlesnakes here, although I am fairly certain the den holds far fewer than it used to, as it was most likely gassed and then burned up by the nearby homeowner.

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Our reluctant friend, 2/11/17

This day was no exception; Michael and I each heard a buzzing rattlesnake beneath the rocks, but in spite of ample sunshine we were unable to locate a single specimen to photograph.  This just wouldn’t do, and so after a brief spell we decided to try a second location I knew of nearby, one with no houses anywhere near it.  This spot is not unlike the other in terms of terrain, although it is slightly more elevated and lacks all the thorny brush.  It contains all the necessary ingredients for a good snake den: rocky slopes with a labyrinthine network of rodent tunnels excavated beneath the largest rocks, protected from northern exposure with an eastern open face, where flat, shelf-like slabs of stone jut from the ground, providing daytime basking opportunities under the rising late morning sun.

So we pulled the truck over and grabbed the hooks.  By this time it was getting on into the evening, and the sun was in the downslide, although the temp as of yet had showed no sign of joining it on its journey.  We hit the western side of the hill, figuring if any snakes were about they’d be thermoregulating here as opposed to the shaded side.  Sure enough, beneath a flat sandstone slab lay a surprisingly fat, dark colored western diamond-back about three feet in length.  The snake immediately bolted for a tunnel which was only inches away, but I pinned it gently with my hook until Michael could come help me wrangle it.  With little difficulty we carried the perturbed serpent to a convenient grassy area in the slanting sunlight, where we set up the camera.

By summertime our sightings of western diamond-backs become so commonplace that we usually offer them little more observance than a safe scoot to the roadside, but four months of winter absence makes our herpers’ hearts grow fonder, and it is always that first February snake that we seem to dote the most attention on.

The thick, lance-shaped head beset with those ever-staring, golden brown eyes with the slit pupils, the menacing, shiny forked tongue dancing with the wind, the telltale dark facial stripe edged in eggshell white, the coiled body composed of tightly compact, keeled scales adorned in rough diamonds, and the contrastingly patterned black and white ringed tail that ends in that most curious of evolutionary adaptation among serpents, the rattle, all combine to help relive the unforgettable outdoor experience that is Crotalus atrox in all its glory.  While Michael’s shutter clicked away I stood still for several minutes, listening to the song of the snake as it rose and fell in pitch and intensity with our movements.  I will have grown so accustomed to the sound by late April after a few trips to the rolling plains, where rattlesnakes seem to outnumber all other reptiles on the roadway.  Still, here and now it is a beautiful serenade, wooing me back into that never completely explored wilderness that serves as my home, my cathedral, my place of solace in a world that seems to grow increasingly mad every time I click the button on my remote control.  Eventually we would return our friend to the edge of the den, where he would make a speedy departure below ground with tail still shaking a future word to the wise, but for the moment I was still lost in that annual reintroduction to herping I always look forward to: the first green light on our great rattlesnake highway.

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Half-tucked into the grasses and hoping we will just go away

Michael: Our biggest venomous snake

At three feet long, the snake we found on this sunny February day was pretty average for its species, but some individuals grow much longer. Most adult diamond-backs you are likely to see in Texas are no more than three or four feet in length, but the most accepted record length is just over seven feet. The internet and social media being what they are, you might see photos of someone holding up a dead rattlesnake at the end of a stick, with the snake appearing to be upwards of ten feet long. Take note that this is a trick of camera perspective, and most of the snakes pictured are nowhere near the length claimed.

The “diamonds” are a series of roughly diamond-shaped blotches, edged with a darker color and then in lighter scales, running from the neck to near the tail, where they become a little more “washed out” and may look almost like darker crossbands. Starting at the tail, the pattern abruptly changes to black and white rings, with the snake sometimes referred to as a “coon-tail” for its vague resemblance to the tail of a raccoon. At the end of the tail are a series of interlocking, dry rattle segments made from keratin, the same stuff that makes our fingernails. A newborn rattlesnake simply has a blunt “button” but will add a rattle segment each time it sheds its skin.

The head is rather chunky, and two diagonal light stripes (one in front of and one behind the eye) run down to the jaw line. The pupil of the eye is elliptical or “cat-eyed,” and between the eye and the nostril, set a little lower on the face, is a pit organ. The pit is a small depression like a hole in the face, and a short distance into the pit is a membrane stretched across it. The pit organs are sensitive to infrared radiation, working like little IR temperature gauges that help the snake “see” warm-blooded animals (like a kangaroo rat that it might eat) or even a warmer spot in a fissure or burrow that could be a refuge from the cold.

Those of us in the Dallas-Fort Worth area live near the eastern edge of this rattlesnake’s range in Texas. These snakes do well in semi-arid to arid habitat, in open grasslands, sparsely wooded savannas, rocky bluffs, thickets, and arroyos. It is a tough, adaptable, common serpent of the plains, prairies, parts of the cross timbers, the Edwards Plateau, south into the thorn scrub and along the Texas coast, and west into the Big Bend country. In parts of the Texas panhandle it is replaced by the prairie rattlesnake. The western diamond-back ranges down into northern Mexico and west through parts of New Mexico, southern Arizona, and a little of southern California. It is also found in parts of Oklahoma and a few places in Arkansas and Kansas.

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A young, light-colored western diamond-backed rattlesnake

The western diamond-back figures in many folk-tales and legends of the American southwest. Writer and folklorist J. Frank Dobie talked about a newspaper report in the 1800’s of a rattlesnake eighteen feet long, but even Dobie had to admit that the “report must have been exaggerated.” His 1965 book, Rattlesnakes, is full of the wild stories told by Texans who had encountered these snakes or heard tales passed down from others. The rattlesnake has worked its way into the culture of every group of people who have lived among them.  In one Native American legend, the rattlesnake was originally the “Soft Child” who was continually pestered by other animals wanting to hear the snake’s rattle. Unable to get any rest or be left alone, the rattlesnake consulted the Elder Brother, who fashioned fangs for him, telling him that whenever someone bothers him, he should bite them. Soon after, the first one to come and scratch the snake was Ta-api, the rabbit. The snake bit the rabbit, who angrily scratched the snake and was bitten again. Ta-api grew sick and died, becoming the first creature to die in the newly-created world. The legend correctly shows the rattlesnake as not inherently aggressive, but needing a way to make other creatures leave it alone.

The truth is that the rattle came after, not before the fangs, as an effective warning: “don’t tread on me.” Animals who live near rattlesnakes do not want to hear that chilling, buzzing rattle, because it indicates that the intruder has disturbed a potentially deadly snake. Tail-rattling when stressed or threatened is common in a wide variety of snakes, and it is thought that the rattle is an adaptation that makes tail-rattling much more conspicuous to other animals (and to people). The sound might warn hoofed animals like deer or bison not to step on the snake, and warn other animals to stay away.

And although the fangs and venom can be a devastating defense, their first use is as a means of getting food. A rattlesnake waiting in ambush at night can use its heat-sensing pits to locate a rat, bite it, and track it down as the rat quickly dies and its tissues begin breaking down because of the venom, as a first step in digestion. Some venom components break down blood or tissue, others interfere with clotting, some attack heart muscle, and some interfere with nerve conduction. When injected into a larger animal, such as would occur in a defensive bite, the venom causes pain, bruising, swelling, tissue destruction, and other effects. Generally, the bigger the dose, the worse the symptoms, and although death from a western diamond-back bite is rare, it is possible, especially if the victim is a small child or someone whose health is already compromised.

Occasionally we find a western diamond-back that is bad-tempered and quick to strike, but we have never seen one that was aggressively “trying” to bite us with no provocation. The presence of the rattle gives us a hint about how dangerous it is for the snake if it has an encounter with a large animal (or human) – so dangerous that evolution selected snakes that were especially good at warning intruders away, giving them a survival advantage. Fighting or attacking a human or other animal might well be suicidal, and so the snakes usually try staying still and not being seen or else running away when possible. Even a rattlesnake that is coiled, rattling, and ready to strike is often backing away at the same time. And so, when Clint and I are in western diamond-back country, we take care to look where we are going so we do not accidentally step on one or put our hands near it. But once we have taken care of that, we see no reason for fear. Respect and caution are important, but there is no need for fear. These reptiles are amazingly adapted to their environments, fascinating to watch and learn about, and beautiful (or at least handsome) to see out in the field. We were grateful to the one that shared a little of its time with us in that late afternoon in February, putting up with being carried on snake hooks and having cameras come at it, striking at us only a couple of times during the whole ordeal. No hard feelings, amigo!

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A western diamond-back from central Texas

Dobie, J.F. 1982. Rattlesnakes. Austin: University of Texas Press.

Rubio, M. 1998. Rattlesnake: Portrait of a predator. Washington, DC: Smithsonian Institution Press.

Werler, J.E. & J.R. Dixon. 2000. Texas snakes: Identification, distribution, and natural history. Austin: University of Texas Press.

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