Science Corner: Venomous Snakes: Part 1

Spring is here, and with its warming temperatures and increasing day length, snakes, including venomous ones, will start becoming more active (although not as much this year in our extended drought as would be expected on a normal rainfall year). While the majority of our local snake species are harmless, there are 3 venomous species which have been documented Kinney County, along with 2 more species that likely occur here as well.

  By far the most common venomous species in our area is the Western Diamondbacked Rattlesnake (Crotalus atrox). This species is so well known that for most of you, a description is unnecessary (although you might be surprised how often I get “snake calls” for rattlesnakes that turn out to be mis-identified harmless ratsnakes or bull snakes) – they are large, thick-bodied snakes with a series of

roughly diamond-shaped blotches down their backs, along with a black and white “coontail” and an obvious rattle. Most adults range from three to six feet, with the largest documented specimen recorded at seven feet, eight inches. Reports of eight-foot-long Western Diamondbacks are a regular occurrence, but such lengths have never been verified. In fact, for years a Freer hide-buyer offered a substantial reward for a legit eight-footer and never had to pay.

  Western Diamondbacks have a reputation for being “aggressive” or “mean” but they are better described as “aggressively defensive” at their most imposing. It is important to stress that these snakes don’t WANT to bite you – injecting venom in a defensive bite means that they won’t be able to use that venom to catch prey for at least a day or two. In my experience, having deliberately looked for snakes in the wild for more than 45 years and having seen literally thousands of Western Diamondbacks, the majority of these snakes if left undisturbed will remain silent, hoping that you won’t notice them and will walk past them without stopping. A personal anecdote illustrates this behavior – I once watched both my Dad and brother step over a Diamondback laying across a narrow trail, and that snake sat still and silent until I noticed it and stopped. As soon as I stopped and alert the rest our group to the snake’s presence, it coiled and did its traditional rattling defensive display. I suppose that this sort of behavior has led to the stories about rattlesnakes “learning not to rattle around people”, but if this is true (currently unsupported by empirical data), then it happened many years ago rather than recently, because its not a change that has happened in my lifetime as far as I can tell.

  Western Diamondbacks feed almost exclusively on rodents and rabbits, with the largest individuals able

to handle adult cottontails and possibly jackrabbits (in the case of the largest specimens). Rattlesnakes in general are capable of eating truly large meals, upwards of 150% of the snake’s own body weight.

 When a snake has eaten such a large meal, it may remain relatively immobile for a few days until the meal has been partially digested. Eating these large meals also means that such a snake gets most of its nutrition all at once, and may not need to eat again for many months. The venom of the Western Diamondback is a complex mix of proteins and enzymes with primarily tissue-destroying properties that in its prey serves to begin digestion before the prey is swallowed. With human envenomations, the result is typically a great deal of swelling in the arm or leg bitten, drop in blood pressure, and without medical intervention death is a possibility, although instances of death are uncommon without medical treatment, and rare with it. 

  The next most common venomous snake in Kinney County is the Texas Coralsnake (Micrurus tener). This is a slender-bodied snake banded with a pattern of black/yellow/red/yellow/black bands or rings on the body. Note that there are multiple records of patternless black or mostly black specimens from throughout Texas, so simple memorization of “red on yellow, kill a fellow” can’t always be relied upon.

  If you do see a banded snake where the red and yellow bands touch, and if you’re in Texas or the southeastern US, its certainly a coralsnake . . . just that sometimes coralsnakes can be just black and yellow, solid black, or mostly red. Coralsnakes are rarely seen, but are not actually rare – they just spend most of their time underground or under leaf litter. Most coralsnakes are relatively small as adults, from 20-30 inches, but the largest recorded specimen was just shy of 48 inches (4 feet!). Coral

snakes eat (almost exclusively) other snakes up to their own size. Coralsnakes are more reluctant to bite than rattlesnakes, and when they encounter a potential predator (you!) their first response will be to

disappear into the leaf litter or brush. If cornered, most coralsnakes will hide their heads, curl their tails, and wave the tail around as if it’s a head. I’ve even seen coralsnakes crawl backwards for a short distance with the tail curled and held up as if it were the snake’s head. If held or grabbed, though, a coralsnake can and will bite. It does not need to bite the webs between your fingers, nor does it need to chew – coralsnakes have fixed front fangs just like their cobra-relatives and can open their mouths wide

enough to bite a hand or a foot. Their venom primarily affects the nervous system by interfering with neurotransmitter receptors (neurotransmitters allow one nerve to pass a signal to the next nerve, or from a nerve to a muscle).

In excess of 75% of all venomous snakebites in the US occur because someone handled a venomous snake. So the first step in preventing snakebite is to not handle them, even if you think or know that the snake is dead. Snakes take far longer to die from mortal wounds than a similar-sized mammal owing to

their slower metabolism, and a snake that is in pain and dying is extremely likely to bite if given the opportunity, and that includes snakes whose heads are mostly destroyed as well. In regards to coralsnakes, I can find no documented instance of a coralsnake biting someone who wasn’t handling one. In the case of coralsnakes, my advice would be to leave them completely alone and let them continue on their way. Although I know its unlikely to be followed, that is also my advice for rattlesnakes. If you do feel a need to remove a rattlesnake from near a home or barn, a long-handled broom and tall trashcan allow you to sweep the snake into then can for transport. In the event that you decide to kill the snake instead, don’t pick it up with you hands for at least an hour after you last see it

moving and then double and triple check. “Dead snakes” can bite. If you decide to skin such a dead snake, have a great deal of care around its head, because you can squeeze venom from its venom glands through the fang and people have been envenomated in such a manner.

  First aid for snakebites is straightforward – call 911 and get to a hospital. Don’t drive yourself unless you absolutely have to (you could pass out). Have a friend drive you to meet the ambulance if possible.

  Take off rings, watches, or anything else constricting your arm or leg that has been bitten. You don’t need to kill the snake and bring it to the doctor for identification – the only thing you need to know was if it was a rattlesnake/viper or a coralsnake. The current “CroFab” antivenom works against all North American vipers. Don’t put on a tourniquet, don’t cut-and-suck, don’t bother with the suction first aid kids, don’t try electroshock, don’t use a cryopack. Try (try!) to stay as calm as possible and get to the ER.

Snake bites also don’t cause allergic responses in the same way as bee stings, and antihistamines like Benadryl have no effect. This is just one example of medical recommendations for snakebite: https://www.hopkinsmedicine.org/health/conditions-and-diseases/snake-bites

I’ll cover our rarer venomous snakes in part 2, as well as suggestions for making your house or ranch less hospitable for snakes.