Snake Bite (Ophitoxaemia)
Venomous Species in Arkansas
(If you've been doing your math, you'll notice that the statistics for snake bite actually accumulate to more than 100%. This doesn't make sense to me either, but I suspect there is a lot of fudge when it comes to that little word "about.")
Here is my list for seriousness of a bite (from least serious to most serious): Copperhead / Pygmy Rattlesnake, Cottonmouth, Timber Rattlesnake / Coralsnake, Western Diamond-backed Rattlesnake. Please note that this assumes a typical bite from a typical-sized animal on a typical adult. There are obviously many, many variables that may affect the behavior of a snake bite, such as:
The following table is a compilation of statistical data (from eMedicine) comparing fatalities per year due to environmental hazards in the US.
Males are more commonly bitten by snakes than females with 50% of all bites occurring in the age group 18-28 years.
An accurate measure for the risk of accidental snake bite is unavailable. It is likely that the vast majority of snake envenomations are due to intentional handling or harassment of snakes. While it may seem inconceivable to some, many people actually keep venomous snakes as "pets." Doing so puts the keeper and their family at great risk.
Composition of Snake Venom
In general, snake venom will fall into 1 of 2 general classes:
But in truth, snake venom is a highly complicated concoction of modified saliva. Each species of snake (and sometimes individuals within a species) will have their own unique formula. In essence, you can think of snake venom as a mixture of "digestive juices."
Potency of Snake Venom
The potency of snake venom is typically determined by conducting an LD50 test. In essence, this test is conducted by injecting a large number of mice with measured amounts of venom. The measured dosage of venom that kills 50% of the mice in a sample (within 24 hours) is the "lethal dose" (thus LD50). The unit is milligrams of venom per kilogram of mouse (mg/kg). The results will vary greatly depending upon the particular methods:
The following table contains information compiled from a variety of sources:
There have been many lists compiled for the most "venomous" or most "dangerous" snakes in the world. Regardless of which list you look at, none of the naturally occurring snakes in Arkansas are ever listed higher than about halfway up. For a sense of comparison, the W. Diamond-backed Rattlesnake is usually listed within the top 2/5ths while the Copperhead is usually near the very bottom. The top spots are typically reserved for Cobras, Mambas, Sea Snakes, and several species of elapids from Australia. In comparison to other parts of the world, the venomous snakes found in Arkansas are "child's play."
Answering a question like "Which of these snake is the most venomous?" requires a lot of assumptions. As a case in point, consider the Coralsnake. The venom itself is highly toxic (drop-for-drop), but then consider the very low venom yield. Of course, a person might really be asking: "Which of these snakes is the most dangerous?" This is an entirely different kind of question. We would then have to factor in a snake's anatomy, disposition, habitat, abundance, etc. Coralsnakes, for example, are relatively small snakes with short fangs and small mouths. As such they are ill-equipped to deliver defensive bites on a human. They are also entirely uninclined to want to bite. In fact, there have been known cases where children have found Coralsnakes and played with them for long periods of time without a sustaining a bite. As far as habitat and abundance goes, Coralsnakes spend the vast majority of their time underground or debris and seem to occur in small numbers. Even finding one is a rare event. But beyond this, as if the "answer" wasn't complicated enough, we'd have to assume that a human would react to a bite in a similar fashion as a mouse!
As a side note, Coralsnakes don't even eat mice! They eat other snakes, and so we can expect that their venom is targeted for this particular kind of prey. For a Coralsnake, a small dose of high-potency venom might be just the thing to immobilize smaller snakes (which may have some natural immunities to snake venom).
There is no scientific evidence that would indicate that baby snake venom is any more potent than an adult's. For the same species, small and large animals will have (essentially) the same venom potency. The differences, if any exists, can almost assuredly be attributed to individual variation rather than age-related variation. Since a larger snake can inject a larger dose of venom than a smaller snake of the same species, it is the larger one that is certainly the most dangerous.
When I ask people, "What is the main purpose of snake venom?", the answer I almost unanimously get back is, "for defense" or sometimes even "so they can bite people!" This kind of answer tells me that most people don't understand at all what a snake's life is like...they've probably never even thought about it.
First of all, venom is very expensive, both from a physiological and from an evolutionary standpoint. This, however, is not to say that some organisms don't have fantastical defensive adaptations, it is just to say that snake venom didn't evolve for this purpose. The fact is, even with highly toxic venom, snakes are often preyed upon by other organisms. Even relatively large Timber Rattlesnakes, for example, have been known to fall prey to coyotes, bobcats, hawks, and even skunks.
So now back to the question... The main purpose of snake venom is for procuring food. For any predator, there is always a danger of injury or even death associated with hunting and taking down prey. Given that snakes often take down relatively large food items and eat infrequently, the dangers are real. A mishandled rat or squirrel could turn upon a snake and inflict life-threatening injuries with their sharp teeth and claws. Venom happens to be an effective tool for such a situation: a quick strike and release, track the prey to the location it finally succumbs to the venom, and the snake has a meal that's ready to eat. The risk of any counterattack is minimized.
For some snakes, it is simply "grab-and-eat", for others constriction, and for others still it's venom. Many people don't realize that their distinction of a "good" snake verses a "bad" snake rests solely upon eating habits! Imagine if my ideas about a person where based upon whether they ate with a fork or a spoon?
As a final note (and this should come as no surprise), snake venom can at times be used effectively as a defensive weapon. For the vast majority of venomous snakes, I believe this is merely an accidental advantage...secondary to the real purpose: procuring food. The exception to this rule may be Spitting Cobras (found in Africa). But if we consider closely the true adaptation for defense in these snakes, it is primarily the placement of the hole-openings on the fangs. I believe to consider the whole apparatus--venom, venom glands, venom ducts, fangs, etc.--as adaptive for defense in these snakes would be misguided.
The more I come to understand snakes and people, the more I am convinced that all snake bites result from human stupidity! (Well, okay, 95% of snake bites in the USA...) This isn't to say that only stupid people get bitten...even the smartest person in the world may have a moment of stupidity, and, of course, it only takes a moment for a snake bite to occur. As a professional who works regularly with venomous snakes, my motto is "think twice, act once." With venomous snakes always in the lab, the danger is in the routine. For nonprofessionals, it may be difficult to believe that changing a snake's water bowl in captivity incurs more risk of snake bite than 100 trips to the field, but it's true. This, perhaps more than any other reason, is why keeping venomous snakes by nonprofessionals is highly ill-advised.
The following list should almost completely eliminate your chances of getting bitten by a snake, even if you spend a great deal of time outdoors:
It may be somewhat comforting for you to know that the naturally occurring venomous snakes in Arkansas are entirely uninclined to want to bite. As a person who works with venomous snakes in the field, on several occasions I (and colleagues of mine) have stepped within inches of a snake, caught a boot-tip under the coil of a snake and half-flipped it over, and even stepped directly on top of a snake. Mostly, these are Timber Rattlesnakes (which almost never rattle!) and are actions that have occurred purely by accident, I assure you! Yet, in none of these instances has anyone sustained a bite, or for that matter was the snake even known to strike. From the perspective of a snake, it must be thinking: Be still, rely on your camouflage to not be seen, survive the encounter. In nature, it's all about survival. If a snake thinks that striking will increase its chances of survival, then it will strike. In most cases, however, snakes will use their "invisibility" to not even be seen or will try to crawl away in a hurry.
Changing the habitat around your property is the best method for reducing the number of snakes where you live. This means keeping your lawn well-tailored, sheds and barns cleared of clutter, and debris (such as old pieces of tin and loose rocks) removed. Essentially what this will do is give snakes (and their favorite prey, mice!) less preferred habitat...so maybe they will move on somewhere else. But even so, regardless of whether you live in the country or downtown Little Rock, there are likely to be some snakes around.
No known "anti-snake" spray, chemical, or barrier is known to be effective in deterring snakes. There are even some brand-name products on the market, but these simply do not work. In fact, some anti-snake measures can be extremely harmful. As a case in point, I am aware of an institution in Arkansas that received complaints from residents about a snake in a creek that was apparently terrorizing the neighborhood. The solution by employs was to dump large quantities of rat poison into the creek to kill the snake. This, of course, killed everything else in the creek, too: fish, crayfish, insects, etc. And apparently no consideration was given to the fact that this poisoned water would eventually flow downstream where children were known to swim and wade! All of this, and the accompanying bad press, could have been avoided simply by asking the advice of people in-the-know. Oh, and by the way, the snake in question turned out to be a completely harmless watersnake.
Hopefully, this story has illustrated the point that people often kill snakes needlessly out of ignorance and fear, without any consideration of their actions. Please remember that destroying or capturing any wild animal may have consequences and repercussions to the delicate balance of nature that we cannot fully understand.
With the assumption that you know you've been bitten by a venomous snake, what to do is actually more simple than people realize. In fact, here is a picture of my entire snake bite kit:
It's easy to carry, almost always with me, and it's not likely to cause damage beyond the snake bite itself. For those of you who aren't quite with me yet, here's the message: find your car keys, get in your car, get to a hospital. That's it! Beyond this, you are simply complicating matters.
But let's suppose you are one who likes to complicate matters... It can't hurt anything to apply basic first aid procedures: stay calm, gently wash the wound with soap and water (if available), keep the site of the bite at the same level as your heart, loosen or completely remove restrictive clothing, shoes, and jewelry around the wound.
For Coralsnake bites only, it may be beneficial to wrap the bite area with an Ace bandage, just as you would a sprain. Leave it on until you are given instructions at the hospital.
No "snake bite kit" (whether of the home-remedy kind or sold on the market) has been shown to provide any benefits for snake bite victims. In fact, the majority of these are known to cause more harm than good. Please read the next section for more details.
At the hospital, you may find that the doctors and nurses have treated very few (if any!) snake bite victims. As such, it is in your best interest to suggest that they consult a Poison Control Center, such as the Arkansas Poison and Drug Information Center (emergency: 1-800-222-1222). In almost all cases, only the symptoms of the bite will be treated. Antivenom should only be administered for very severe bites.
Although the list is long, and includes a vast array of traditional and home-remedy solutions, suffice it to say that if it isn't mentioned as something to do above, then don't do it!
Antivenoms, in general, come in two varieties:
For snake bite occurring in the United States, these are likely choices for treatment:
Species identified by an asterisk (*) indicate venoms used in the actual production of the antivenom. In addition, a company in Mexico, Instituto Bioclon, produces two equine-derived antivenoms that may be used to treat snake bite from North American species: CORALMYN for coralsnake envenomations and ANTIVIPMYN for pitviper envenomations.
The production of antivenom involves hyperimmunizing ungulates (sheep or horses) by injecting them over time with increasing quantities of snake venom. Blood is then drawn and fractionated to refine and concentrate the serum globulins. Add a couple of preservatives, such as Phenol and thimerosal, some distiled water, and you have an antivenom. The antibodies produced by the ungulates to combat the toxins in the venom now become the active ingredients in the antivenom.
Antivenom should only be administered by trained professionals for very severe snake bites. Some people have a severe allergy to antivenom (especially those derived from horses) and a skin test is usually standard procedure. Without using caution, the antivenom itself could potentially send someone into life-threatening anaphylaxis! Depending upon the severity of the bite, treatment may require 4 to 18 vials or more. Most antivenoms have no maximum dosage; only it is advised to use the minimum dosage necessary to counteract the effects of the venom.
The cost of antivenom will vary according to the market, but given that it is expensive to produce and generally in low demand, the price PER VIAL is likely to be $500-1000! (Remember that several vials are typically required to treat a bite.)
Due to the cost, relatively short shelf life, and concerns over allergic reactions, few snake researchers or hobbyists maintain their own antivenom stockpiles. For native species, antivenom is usually available quite readily, but the same cannot be said of exotic species. As part of their snake bite emergency plan, those keeping exotics usually research the location of the nearest available antivenom. Antivenom banks have become popular as a way for keepers to divvy up the costs of maintaining antivenoms for exotic species.
A person bitten by a nonvenomous snake can expect nothing more than a mild to moderate "pinch" from the bite. The sharp, stinging sensation associated with most venomous snake bites will be absent (think red wasp sting, only worse). The bite may be a lightning-fast strike and release or a "chomp and chew", depending upon the species and mood of the snake. The bite wound will typically consist of 4 curved lines of tiny pinpricks. These correspond with the rows of sharp, pointy teeth. The bite may bleed more than one might expect, due to the sharpness of the teeth and anticoagulant properties of the snake saliva. In some cases, the bite area may mildly itch. I've found that Watersnake and Gartersnake bites seem to cause more of an itching sensation than other snakes.
A nonvenomous snake bite should be treated just as you would any other kind of skin abrasion: wash the wound with mild soap and water, apply antibiotic ointment, and bandage.
Although turtles and some other reptiles are known to carry Salmonella, I am aware of no cases of transmission from snakes to humans. I am, however, aware of just a couple of reported cases of tetanus poisoning associated with snake bites. These cases have been reported in other parts of the world where inoculations against tetanus are rare and the bites in question involved the deep puncture wounds of venomous snakes. In other words, the risk of transmitting any disease associated with nonvenomous snake bites is virtually zero. The same also holds true for venomous snake bites, but there is definitely a greater risk of secondary infection with venomous snake bites.
I have been bitten by nonvenomous snakes hundreds of times. If it is convenient to treat the wound, I may wash it off, but most of the time I do absolutely nothing. I have never had a nonvenomous snake bite become infected or cause problems in any way.