FAQ: Venomous Critters

An interesting summary on poisonous snakes, spiders, lizards, and scorpions, with up-to-date treatment. Worth reading, and rather humorous besides. Especially good for those moving to the southwest or southeast!

Venom Nation

Vipers, spiders and scorpions. A traveler’s guide to our poisonous pals.

Within the United States there are five groups of dangerous venomous animals that travelers might expect to encounter: pit vipers, coral snakes, scorpions, spiders and lizards (two other groups – centipedes and stinging insects like bees, wasps and ants – are generally not lethal.) Which ones are the most poisonous? Any attempt at classification results in qualification. This much can be said: The venom of rattlesnakes is responsible for more deaths, more hospitalizations and more crippling injuries than the venom of any other animal in North America. Below is a field guide to each of the five venomous groups, how to avoid them – and what to do if it’s just not your day.

Pit Vipers

So called because of the heat-sensing “pit” or opening beneath each eye that’s used to track prey in darkness, this family of snakes includes three species: Crotalus( the rattlesnakes, of which 32 species and 65-70 subspecies have been identified in the US alone), Agkistrodon (copperheads and cottonmouths) and Sistrurus (pigmy rattlers and massasaugas).

Bites from any of the, even the most potent rattlesnakes, rarely result in death. Still, if you are bitten get to a hospital. Don’t apply a tourniquet or ice. Don’t use a snakebite kit. Don’t cut the puncture wound and try to suck out the venom. In fact, there is no good first aid for rattlesnake bite. “We’d rather tell people that than have them doing the wrong thing and lose their life or an arm,” said Boyer. If you must do something, she said, “elevate and immobilize the limb, rest quietly, and don’t freak out.” Most of the popular literature on snakebite is out of date, and some hospital emergency-room physicians may still attempt to use ice. Some may even want to do surgery. Don’t let them. Almost all cases of amputation after snakebite are actually the result of using ice, a tourniquet or both. Surgery is necessary only in extremely rare cases. If you’re not in an area where snakebite is common, insist that the doctors call the Regional Poison Control Center (listed on the inside cover of the phone book).

The sole treatment is a 1950’s era rattlesnake antivenom made from horse serum (antibodies derived from the blood of horses), which is reasonably effective in most cases. But almost everyone who is treated with rattlesnake antivenom can count on some level of serum sickness – a natural allergic reaction. Still, that is usually preferable to the effects of untreated snakebite. Boyer said, “It’s a lousy, stinking product that causes a lot of problems, but there’s nothing else around.”

The cure for snakebite is to avoid it. It’s not that difficult. Snakes generally shun people. If you see one, move away from it. A rattlesnake can strike an object up to a distance equal to half it’s body length. The largest rattler on record in the US was around seven feet long, so if you remain just four feet away from any snake you encounter, you can take photos, you can sing Pink Floyd songs, but you’re unlikely to be bitten.

Some people like to chop the head off a rattlesnake and take it with them. Bad idea. A rattlesnake can bite up to an hour after decapitation. A “spasm” from a dead snake will reflexively deliver the full load of venom and can be worse than a live snakebite. It’s nature’s way of telling you: Leave them be.

The question most people ask: Am I going to die? The answer: Yes, but probably not today. While envenomation by a pit viper can result in the loss of a finger, hand, arm or leg, in the US it’s not likely to be lethal.

Coral Snakes

Members of the family Elapidae include cobras, mambas, kraits, and coral snakes. There are two species of coral snakes in the US, the eastern coral snake and the Arizona coral snake. The eastern coral’s venom is a powerful neurotoxin that, on occasion, has caused deaths. At first there may be no symptoms, and local injury is often small with little swelling or tissue damage. But within a few hours, the victim may experience a cascading sequence of symptoms, beginning with lethargy, nausea, weakness, and trembling or twitching. This leads to convulsions, paralysis, respiratory failure and, in some instances, death.

No deaths from Arizona, or western corals have ever been reported.

Coral snakes are brightly colored with broad bands that encircle the body, making a pattern beginning with a black snout; black, yellow, red, yellow, black, yellow, red, yellow. The yellow may appear white or ivory. Unlike rattlesnakes, coral snakes have round (not elliptical) pupils and fixed fangs. The Arizona coral snake lives in southern Arizona, the southwest corner of New Mexico and Texas. The eastern coral snake, which is larger can be found in North Carolina, South Carolina, Arkansas, Alabama, Georgia, Mississippi, Florida, Louisiana, and Texas.

People have come to believe they can handle coral snakes with impunity because they won’t bite. Some say they can even use a coral snake as a bracelet. The fact is that coral snakes bite unpredictably. It is difficult for a coral snake to bite a human, because of it’s fixed fangs and small head (even in the larger eastern coral snakes). People often handle them for hours without incident, only to be bitten for the reasons that only a coral snake could tell you.

Venom is delivered via grooves in the teeth, rather than injected by hypodermic action, which is why coral snakes like to hang on for awhile. If you are bitten, pull the snake off. The less time you give it, the less venom you get. A bite by an eastern coral snake is a major medical emergency. Get to a hospital immediately. There is a horse serum antivenom for the eastern coral snake, and it is the only effective treatment. No antivenom exists for the western coral, whose bite is usually not fatal. But hospital care is important, and a tetnus shot is probably a good idea.


Arthropods have been on earth more than 400 million years, but only one species in the US is potentially lethal, the bark scorpion. It is confined mostly to the southwest. Mexico is home to seven lethal species.

Once you have seen a scorpion, you won’t forget what it looks like; claws that snatch and a hooked stinger hovering on a five segment tail. They come in colors ranging from straw to pink to brown to black and in sizes from an inch or less to five inches. The most common in the southwest is also the largest, the giant hairy scorpion, but its venom is not considered dangerous. As a rule, specialists say, the thicker the claws, the less dangerous the scorpion; the viciously venomous ones usually have slim pincers. The bark scorpion is generally straw-colored with elongated tail segments – and slim pincers. It is only about an inch long at maturity.

Bark scorpions are so called because they like to hide in the bark of trees. Unfortunately, they also like to hide in the drains of your sinks or in your shoes at night. They like any moist, dark, protected place. A sweaty shirt thrown on the floor might make an inviting hideout, too.

The scorpion grips its prey with it’s crablike claws and then whips its tail over its back to inflict a sting. (Scorpions do not bite.) As with snakes, 90 percent of stings are on hands or arms. Some first aid can help. Ice and acetaminophen are good for pain relief. Apply a single ice cube, 10 minutes on, 10 minutes off. (Don’t immerse the wound in ice water.) If the victim is a child, a visit to the emergency room is in order.

Bark scorpion venom contains at least five potent neurotoxins. Its sting is very painful, though the wound may not swell much at first. It is generally not life-threatening to healthy adults. The classic symptoms of a serious reaction, usually seen only in children, include uncontrollable thrashing of the arms and legs and roving eyes. Adults may experience mild twitching of the facial muscles, cramps, nausea and anxiety. Infants are especially at risk of respiratory failure. Though some 8,000 scorpion stings are reported in Arizona alone each year, there have been no fatalities since 1958.

Although antivenom is given for scorpion stings in Mexico, none has been approved by the FDA for use in the U.S.

Black Widow Spiders

All five species in the United States, including the black, red and brown widows, are poisonous. Only females have fangs long enough to puncture human skin and inject venom.

The black widow is shiny black with a body the size of a nickel and a red hourglass marking on its stomach. The hourglass may also be yellow or orange. Its characteristic web is tangled, strong, nd chaotic looking (like the fake spider web that people spread around at Halloween). They are found in any protected place indoors- closets, attics, basements – or outside, under woodpiles, animal burrows, barns and beneath ground cover.

Mature females tend to stay in their webs. They don’t prowl. The black widow lies in its web and bites when the web is disturbed. The classic human encounter involves a spider that spins its web back and forth across the the seat of an outhouse to catch flies that move back and forth through that opening. “More men and boys are bitten in outhouses because they have dangling appendages,” Jude McNally said.

Black widow spider venom is a powerful neurotoxin. There may be two puncture wounds and a pale coloring to the skin around them. Major pain begins in about half an hour, an ache that tends toward numbness. Systemic symptoms may takeup to two hours to appear. Muscle pain near the bite spreads to the abdomen, back, and legs – or it may simply appear in those locations. Other symptoms include difficulty in breathing, muscle twitching, anxiety, swelling of the eyelids, headache and nausea.

But don’t wait for symptoms to appear. Go to the emergency room where you mayreceive muscle relaxants and narcotics for pain. An antivenom exists, but allergic reactions to it may be much more severe than the spider bite itself. It is recommended only for pregnant women or for cases involving hypertension, seizures or respiratory failure. Deaths are very rare; none have been recorded in the United States in more than 15 years.

Brown Spider

The 12 species in the US (out of more than 100 that are known) include the infamous brown recluse spiders and the Arizona brown spiders. All are seriously dangerous to humans. Called “violin spiders” because of violin shaped marking on the back, the brown spider’s body is usually a half to a full inch in length. Their legs are two or three times as long as their bodies. Colorings can vary from gray to orange to rust to brown. Unlike other spiders, which have four pairs of eyes, browns have three pairs.

Brown spiders range across the south and southwest and up through Iowa and Illinois (but no farther north than southern Wisconsin). They like to hide in dark corners indoors, or under objects or in the nests of animals outdoors. Their webs are dense, disorganized, sticky and very white or tinged blue.

Spider venom is injected through a hollow fang. Spiders bite, they don’t sting. Like most venoms, the substances injected by the brown spiders will digest tissue. People who have been bitten by a brown spider often feel nothing at first. But an aching sets in at the site after six to eight hours, as blood vessels are closed off by the poison and tissue begins to starve. A blister appears and there may also be flulike symptoms. The blister breaks, leaving a black area of dead or dying tissue. The bite may appear as a dark spot, with a white area surrounding it and a red ring around that – the so-called bull’s-eye lesion. Fortunately, spiders are small and people are big, and fatalities are extremely rare in the US. More commonly, the bite of a brown spider results in an ugly black patch of dead tissue that rots and falls off after a few weeks, leaving a deep ulcer that takes many months to heal.

If bitten, go to the emergency room. don’t wait for symptoms to appear. A severe reaction may range from nausea to a high fever that can last a week. In most cases, analgesics (such as aspirin) are given for pain while doctors watch for systemic reactions. Usually nothing more is required. An antivenom is being tested.

Gila Monsters

There are two venomous lizards, the Gila monster and the Mexican beaded lizard. The Gila monster lives in the Sonoran Desert across southwestern Arizona and down into northwestern Mexico, as well as in the Chihuahuan Desert in northwestern Arizona, the southern tip of Nevada (around Las Vegas) and the southwestern corner of Utah (vicinity of St. George). They also live in a small area in eastern California. The Mexican beaded lizard occurs in Mexico only.

The markings on these saurians are never quite the same, yet no one seems to mistake a Gila monster for anything else. They are usually black and pink (or coral) colored. The largest lizards in the US, they can reach 20 inches in length, and the largest specimens can weigh up to two pounds. The Mexican beaded lizard is a similar looking animal with a longer tail than the Gila monster. It can grow to three feet in length. Think about it.

Most active in March, April, and May, Gila monsters are not easy to find. They don’t crawl up and bite people. They are slow and torpid animals. Since it’s virtually impossible to be bitten without picking the animal up, don’t pick up any Gila monsters.

Their delivery of venom depends on how long they can hang on and chew. If you can get their jaws pried open and take your hand out of the lizard’s mouth, chances are that little venom will enter your system. Trying to shake the lizard off won’t work well. Place it on the ground and pry its jaw open with a stick, knife, or other tool. Some people suggest holding a flame beneath its jaw or submerging it in water, or even squirting lighter fluid on its snout. This last technique presents us with the possibility of someone running in circles with a flaming lizard attached to his hand. The bite is reported to produce “instant and excruciating pain.”

Gila monster venom is similar to rattlesnake venom in its action. Because the venom contains fewer of the anticoagulant agents and digestive enzymes, tissue damage will be lessened or absent. Gila monster bites are rare. But the venom is highly toxic and there’s no way to tell how much you received. Weakness, dizziness and shock could result. That may not be a reliable criterion, since some people grow weak and dizzy at the very thought of having a lizard attached to their hand. No human deaths resulting solely from Gila monster venom have been documented.

No antivenom exists. The most important thing the docutor can do is remove the Gila monster’s teeth, which break off in the wound and cause infection. A tetanus shot isn’t a bad idea either. It’s impossible to give this advice often enough: Don’t apply ice or a tourniquet. Do remove the lizard. Do get to a hospital.

If you do happen to die from a Gila monster bite, they will probably erect a statue on the spot.

Excerpt from Men’s Journal March 95