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Wildlife of the Desert Southwest - Rattlesnakes and Snakebite

Page 1: Rattlesnakes
Page 2: Cougars

Page 3: Coyote
Page 4: Lizards
Tamarisk Beetles

The southwest desert has a very diverse selection of animals- mammals, reptiles, amphibians and birds. Rather than try to describe the attributes of each, I will give an overview of those you might expect to see, might hope to see, and those that you might not want to see. Visit our Guidebooks page to find recommended field guides on desert wildlife. Be sure to look at our Tracking Pages for information on tracking and observation.

Warnings and Available Data

First, my warning and disclaimer- I am not a doctor, nor a herpetologist. The information I provide below has been collected from sources readily available to anyone. I have merely summarised and compiled the data I have collected for easier reading. I have included my own observations, experiences, and knowledge of rattlesnakes. I assume no risks for the use of the following information- it is for informational purposes only. Once you read this page you are on you own to choose how to react to snakes and snakebite should you be faced with such decisions.

To summarise my findings, all indications are that if you are bitten by a rattlesnake, and venom is injected, you will most likely die without medical attention. My research goal was to confirm this, and to find out the odds of survival, the possible long term damage, and overall risk involved in the event that medical attention was not available. I am still in the process of answering these questions; it appears that they have not been asked before.


Compared to other parts of the world, there are very few animals in the southwest desert that are a possible threat to humans. If I were to list them in order of threat potential, the rattlesnake is number one. I have encounters with them at least a couple of times every summer and in recent, dry years it has become at least four times a summer. With that in mind, I really do not want to refer to rattlesnakes as “dangerous”, although they certainly can be under the right circumstances. It is important to remember that they are doing nothing more than living in their own territory under their usual conditions, and that we are visitors in their land. If we exercise caution and are mindful of our surroundings while hiking, we will remain safe.

Crotalus viridis lutosus- Great Basin rattlesnake.
Great Basin Rattlesnake- Crotalus viridis lutosus- photographed near Cedar City, southwest Utah. I encountered this snake immediately after getting out of my truck at a site I chose for a camp. I did not startle it; it didn't coil or rattle. After turning its head towards me and acknowledging my presence, it went on with its business of searching for food. I sat down and watched it for an hour or so, during which time it moved only about 30 feet. Once I knew it was safely off in the distance, I chose to forego the stars and set up my tent for the night.

Local Species and Other Venomous Snake Species

Rattlesnakes are pit vipers, in the family Crotalidae. The primary species found in Utah is the Western Rattlesnake, Crotalus viridis. In southeast Utah and into Colorado it is found in the subspecies known as the Midget Faded Rattlesnake, Crotalus viridis concolor. I have met these little snakes on trails, roads, canyon bottoms and off in the bush more times than I care to remember. They can often be found mid-day at the base of rocky outcrops resting under rocks or sagebrush, and at dusk as they head out to hunt. On a recent encounter, I came about a foot from a young one, 10 inches long, with just two small black buttons. It was too small to make a sound although it was trying.

The literature states that these snakes have venom 10-30 times more potent drop for drop than other rattlesnake species, so do not let their small size fool you. This may be due to a neurotoxic component in their venom which makes it more potent. As a rule, size does not necessarily correlate to venom strength. Many other factors are involved, and are discussed below.

In southern Utah and into Arizona you may also encounter the Hopi Rattlesnake subspecies, Crotalus viridis nuntius. In western Utah and into Nevada the subspecies found is the Great Basin Rattlesnake, Crotalus viridis lutosus.

The second venomous snake species in the U.S. is from the family Elapidae. These include two species of coral snakes found in the southern U.S. and one species found in the southwest. The Arizona coral snake, Micruroides euryxanthus, is found in southern Arizona, southwestern New Mexico and south into Mexico. Coral snakes have a neurotoxic venom. They are identified by their red, yellow, and black banding.

Types of Venom and Toxicity

Rattlesnake venom is a potent mixture of many toxins, but there are three main components. Hemotoxins, which seem to be the most common toxins and are the primary toxins in most rattlesnake venom, destroy tissue, organs and disrupt blood clotting. Cytotoxins attack the cells, causing necrosis and death of tissue. Neurotoxins, the quickest acting, most potent, and dangerous component in rattlesnake venom, attacks nerves. It is unclear in the literature how snakes are classified as hemotoxic or neurotoxic, but it is likely based on the percentage of the toxins in the venom. The Mojave Rattlesnake is noted as being the only rattlesnake possessing neurotoxic venom.

However, in recent years neurotoxic components have been increasing in frequency in other rattlesnake species. Recent literature states that there has been a visible increase in the number of bite victims experiencing neurotoxic effects. There are a number of reason this may be occurring. Some scientists believe that rattlesnakes are adapting by increasing the toxicity of their venom as their prey becomes more immune to their bite. Others speculate that all rattlesnake species posses some degree of neurotoxins and that the recent increase is simply due to more bite incidents caused by increased human encroachment on their territory. I have a personal theory that the recent hot and dry weather may be affecting the potency of snake venom, causing it to be more concentrated if a snake is less hydrated (this is merely a theory- I am not at all familiar with levels of snake hydration and their affects on snake physiology).

Factors Affecting Envenomation and "Dry Bite" Frequency

According to the Food and Drug Administration in a 2002 revision of an article in FDA Consumer, all snakebites should be considered medical emergencies, although different amounts of venom with varying degrees of toxicity may have been injected. The article states that “in the U.S. between 7,000 and 8,000 people are bitten by venomous snakes each year…with only about 5 of those bites resulting in death.” So your chances are good for survival.

The article also states that “20-30% of patients seen who have been bitten and who actually have fang marks may not have received venom at all". Other articles I have found put this rate for so-called "dry bites" between 10 and 50%. The reason for these dry bites may be that while a rattlesnake is hunting for its food it is fully aware of when and where it will strike, making the injection of the venom very accurate. If a snake is disturbed during its rest and strikes, the accuracy of its timing of venom injection may not be as exact. In this case you may even find the venom on a pant leg or boot near the bite area, a welcome sight if you are bitten far out in the bush. Additionally, some snakes may not inject venom at all, or may inject only a small amount.

Envenomation amounts and degrees of toxicity vary between species and are also affected by such factors as nutritional status, season, age and size of the snake- some smaller snakes may have less potent venom. Even time of day can effect amount of venom- if a snake has been hunting during the night, your chances "might" be better with a morning bite that you'll receive less venom.

Basic and immediate signs of envenomation include severe pain, rapid swelling and bleeding. Other signs that may occur include nausea, vomiting, general weakness, shortness of breath, and diminished vision. Signs such as discoloration of tissue to purple or even black, low blood pressure and tingling of lips and tongue indicate more advanced symptoms, or potentially more toxic venom.

"First Aid" and Treatment Myths

Recommended first aid for a snakebite is rather simple:
Remove any constricting clothing
Wash the bite with soap and water
     Cover the bite area with a clean, dry dressing
     Immobilize the bite area and keep it lower than the heart
     Keep the victim calm and comfortable, administer psychological first aid
     Treat for shock
     Monitor vital signs- pulse, breathing, temperature and blood pressure if possible
     Get the victim to medical help immediately

If you cannot reach medical help within 30 minutes, the FDA article recommends placing a loose bandage (also known as an Australian wrap) a few inches above the bite- do not apply a tourniquet. The bandage should be loose enough to slip a finger under. Check it regularly and loosen it if the area swells. The idea is to constrict lymph flow, not blood flow. I have found one reference stating that after thirty minutes the venom has been "set" and the bandage can be removed. At this point the victim can be moved, or if you are alone, you can start walking. This has not been confirmed by a medical professional.

Finally, here is what not to do if bitten:
     Do not give the victim liquids, medication, alcohol, or caffeine
     Do not apply ice
     Do not use a tourniquet
     Do not cut the bite area in order to suck or draw out the poison.

Suction of the Bite Area

Suction of the bite area is controversial. A suction device can be applied to the bite area and may help to draw out some of the venom. This may be the most effective, and only, field method of actually helping reduce the effects of envenomation. A suction device called The Extractor, made by Sawyer Products, can be found at most outdoor stores and is also available through our website from This kit is touted as being the best, most effective kit on the market. Directions state that it should be used immediately after a bite; to be most effective this should be within the first three minutes. According to one study, the suction device can remove as much as 34% of the injected venom if used immediately, but this has been disputed by a later study (see "Suction as Initial Treatment...." poster). For a review of the Sawyer Extractor by someone who actually had to use it, click here. I carry this kit, but gratefully, even with snake encounters on nearly every trip, have yet to use it and hope I never have to.

On a recent call to the Poison Control Center, I asked about the Sawyer Extractor. The person I spoke with was not familiar with it specifically. I explained the device, and the claims that it can remove about 30% of the venom. He noted that with 30% of the venom removed, you still have 70% of it in the victim. Depending on factors such as the type of snake and the amount of venom injected, 30% of the venom removed could be a negligible amount. His point was that you should seek medical attention, and not waste precious time with suction devices. I will still carry the Extractor with me- if there is at least some chance that it might help save my life, it’s worth the few ounces of weight.

Reality, and the Final Word on Snakebite

I have called the Poison Control Center (800-222-1222) numerous times over the years and asked the same questions about rattlesnake bites. I have always asked what to do for snakebite, and have only been given the answer "seek medical attention". I have always asked what should be done if you are bitten by a snake four days down the San Juan River, or worse, at the bottom of a canyon with four more days to walk, when medical help may not be an option. The answer has always been the same- "seek medical attention". But on my most recent call the doctor I spoke with went out on a limb and gave the answer I had been expecting- "seek medical attention, or die". That is all. There is no field treatment for snakebite. There is the above-mentioned first aid, but that is nothing more than to stabilise the patient. In his words, the only way to insure safety is to carry some means of communication- a satellite phone, or maybe a Personal Locator Beacon (PLB)- that can help get you to a hospital no matter where you are. (Use caution if you carry the PLB- they are being abused- read more here.)

Future Goals

As with all the topics on the Desert Explorer website, I update and add info as time allows. I will continue seeking confirmation of first aid and treatment of snakebites. I will continue looking for data on the odds of survival, the possible long term damage, and overall risk involved in the event that medical attention is not available, and post my findings. I will add information on antivenom in the near future.

See all our PLB research data by clicking here.

See 29 October 2009 blog post for update conversation with Poison Control Center, as well as more PLB info.

Links and Resources

Back to Top

Page 1: Rattlesnakes
Page 2: Cougars
Page 3: Coyote
Page 4: Lizards
Tamarisk Beetles

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