Texas Tech University

The Truth About Snakes

Snakes from Department of Biology are big attraction at Arts & Sciences Day 2018, TTU photo by Toni Salama

Like the Sinuous Reptiles Themselves,
Most Fears Haven't a Leg to Stand On

Written by Glenys Young

Many years ago, Texas Tech University biology professor Lou Densmore went to Silver Springs, Florida, while studying crocodilians. Home of many Eastern diamondback rattlesnakes, Silver Springs had pits where captured snakes were kept, and when time came to clean out the pits, the rattlesnakes were transferred into large trash cans.

For safety purposes, the trash cans had lids, and anyone removing a lid was supposed to handle it with tongs.

"There was one 17- or 18-year-old kid who grabbed the top of the thing and pulled it, and the snake struck," Densmore recalled. "If you look at that big vein in your wrist, one fang hit that. He was unconscious in two minutes and dead in 20. The facility removed all venomous animals due to that incident.

Biology Professor Lou Densmore with a snake from the lab"It's a real rare situation, but I talked to the people at the emergency room and they said even if he'd been bitten in the ER, they couldn't have saved him. It was a 4.5-foot Eastern diamondback, and the big Easterns probably give more venom per bite than any other snake, at least in North America."

Hearing stories like that, it's not hard to understand why so many people are afraid of snakes. In addition to real-life accounts like this are the many instances of nefarious snakes in our culture—from the Biblical serpent whose trickery forced Adam and Eve out of the Garden of Eden and the evil Medusa in Greek mythology, whose hair was actually live, venomous snakes, to popular culture appearances in Indiana Jones and Harry Potter.

Even science contributes to this perspective.

"Fear of snakes is inherent in primates," Densmore said. "They've tested with flashcards and, for many primates, a snake elicits a different facial response, generally anxiety or concern. It's in our genes: something about serpents is probably not right."

Despite all that, it's important to remember that snakes are not really evil; they're just trying to survive.

"The thing we like to tell people is that snakes aren't monsters, they're animals," said Mark Lee, a graduate teaching assistant in the Department of Biological Sciences. "So when they react to people, it's a defense mechanism. People say, 'The rattlesnake came at me,' but they are always defensive. Given the chance, the rattlesnake will always choose to escape."

Snakes on Self-Defense

The problem, Densmore said, comes when a rattlesnake incorrectly interprets the situation: It knows it can't eat a person, so it assumes the person is trying to eat it.

snake from Department of Biology is popular at Arts & Sciences Day 2018, TTU photo by Toni Salama"Even a rattlesnake has a lot of predators," explained Lee, who helps care for and maintain Texas Tech's collection of venomous snakes. "Coyotes, eagles, roadrunners, bobcats, raccoons, hogs—a lot of things eat rattlesnakes, even though they're venomous, so they have to be wary. And as far as reacting defensively to people, a lot of people do kill rattlesnakes. But snakes never attack; it's always defense.

"So if you see a rattlesnake rattling, just take a couple steps back and it'll take an escape route in the opposite way from where you're going, most of the time. Sometimes, if it sees a hole behind you, it'll go for that and it'll look like it's coming at you—that's where the myth of snakes chasing people comes from."

Just as a rattlesnake rattles its tail to keep predators at bay, other types of snakes also have some dramatic defense mechanisms. Bull snakes make a loud hiss, the hognose snake plays dead and the Texas long-nosed snake may be the most impressive of all.

"If you've ever heard of the horned lizard, one of the things it can do is shoot blood out of its eyes. These guys can do something similar, but they're a little more dramatic about it," Lee said. "They actually shoot blood out of their cloaca, which is basically their butt. They shoot blood and feces and musk all at once. The first time I caught one, I didn't know that, so I thought I'd hurt it."

"Almost every snake, the first time you catch it, will musk on you," Densmore said, matter-of-factly. "That's a good defense mechanism. Most things don't like to get snake musk on them."

Venomous vs. Nonvenomous

One of the things that makes people nervous about snakes is that some are harmless and some can be deadly—and to the untrained observer, it can be difficult to tell which is which. To further complicate matters, even the methods intended to help distinguish between safe and unsafe snakes are not foolproof.

non-poisonous snake at Arts & Sciences Day 2018, TTU photo by Toni SalamaFor instance, the simple rhyme "red on yellow, kill a fellow; red on black, safe for Jack" can help identify the venomous coral snake, whose red and yellow bands touch, from its nonvenomous impostors like the milk snake—but only some of the time.

"The big problem with the Texas coral snake is it has black splotches in the red," Densmore explained.

And, although it's rare, there are some aberrant coral snakes that are any color. Lee has seen some without yellow stripes and some that are completely black, red or white.

"The nursery rhyme is only 99 percent effective in the United States," Lee said. "And if you go south of the border, it doesn't mean anything."

"You get more than 50 miles into Mexico, you better forget you ever learned that little jingle," Densmore added. "If you get to Central America, it can absolutely be deadly. The coral snakes down there will get over 4 feet long, and their venom is actually stronger than you'd see from a king cobra. The corals we have in Texas are pretty small, most don't inject much venom even though it is a potent neurotoxin, and their mouths aren't that big either, so they almost have to bite you in the skin between your fingers. That simply does not happen very often."

Another typical method of distinguishing venomous from nonvenomous snakes is to look at the snake's eyes—but that's not perfect, either.

"If you ever hear rules to distinguish venomous snakes from nonvenomous snakes, something you might hear is the pupils: Rattlesnakes have elliptical pupils—and that's true, but only in certain situations," Lee said. "In areas of low light, rattlesnakes will actually expand their pupils to let more light in. And in areas of high light, other snakes' pupils will restrict.

"For everything in nature, there's a rule and there's always an exception. The best thing to do is to learn how it looks as a whole, not just little pieces. If you learn to spot the venomous snakes, you'll know that everything else is safe."

Myths about Snakes

Several widely held beliefs about snakes add to their fear factor.

The first is that because feral hogs eat rattlesnakes, the rattlesnakes are now evolving to rattle less, which means that unwitting humans who come across one won't have any warning.

snake from Department of Biology is popular at Arts & Sciences Day 2018, TTU photo by Toni Salama"We hear that lot. It's probably not true," Lee said. "Rattlesnakes vary in how much they rattle, individual to individual. Some rattlesnakes won't rattle if they think you don't see them. A lot of times somebody can walk right by a rattlesnake and not even know it because the snake knows he's camouflaged and he's not going to announce his presence. That's something they've always done.

"Something I've noticed is that larger rattlesnakes tend to rattle less because there are fewer things that can eat them, and baby rattlesnakes rattle all the time."

The latter are the focus of another myth: that baby rattlesnakes' venom is stronger than that of adults. This isn't strictly true, Lee said, but it's understandable that people have that perception.

"Rattlesnake young have smaller venom glands than an adult rattlesnake," Lee explained. "A six-foot Western diamondback has a very large venom gland and a lot of venom—a lot more than a baby could even hope to hold—but the adults have more control over their dosage. Sometimes you'll see what's called a 'dry bite,' where they'll bite but not inject any venom—it's a way of scaring you off.

"Venom is very expensive to produce, and snakes don't want to waste it on every person who walks by, so if they're running low or they're hungry and need the venom for food, they'll give a dry bite. Baby rattlesnakes cannot control it as well, so they will empty their entire tiny, little venom gland."

That said, an adult who isn't saving its venom for food might not control how much it injects.

"If a rattlesnake has just eaten and you're threatening him, he can give the whole dose," Lee said. "A big diamondback can give the whole dose, and that's going to be a lot more dangerous."

If You are Bitten

As Densmore witnessed in Florida and Texas, rattlesnakes can strike from up to half their body length away, so both men recommend taking some simple precautions to stay safe. When gardening, doing yardwork or collecting firewood, be mindful of where you put your hands. Another good tip is to snake-proof your yard—remove anything just lying around that a snake could choose to hide in.

snake from Department of Biology is popular at Arts & Sciences Day 2018, TTU photo by Toni Salama"I think the most important thing is, when you're outside, always look down ahead of you," Densmore said. "Have something you can beat the grass with, especially in places where you haven't been. Always look every two to four seconds—bring your eyes down.

"The closest I ever came to being bitten, I was walking down a stream bed not too far from Houston, and I was bird-watching. I happened to look down and there was a water moccasin just a few feet away from me. But he was eating a catfish, so he couldn't have bitten me."

Most people who get bitten are either handling snakes or trying to kill them, Lee said.

If you are bitten, it's important to know what to do.

"Whatever you do, don't ever put a bitten limb on ice or something like that; if you do, you're really looking for gangrene," Densmore said. "We used to tell people you always keep the bitten limb down. Now, the most recent medical advice is, for a rattlesnake bite, you try to keep it equal, straight out from the shoulder.

"Rattlesnake bites are serious enough that, if you hold the arm on which you have been bitten down, there's so much venom in there it can cause really serious damage to your hands. People who end up losing fingers or getting amputations, that's what happened. At the same time, you never want to put it above your head because then gravity moves it toward your heart. So with rattlers, keep the limb straight out from the shoulder. If you know it's not a rattlesnake, but you think it was venomous, then keep it down."

A nonvenomous snake bite can just be washed with soap and water, Lee said. And how do you tell if the bite is venomous or not?

"You can tell by the pain you're feeling," he said. "With a rattlesnake bite, they hurt—unreal. I've heard it described as someone hammering a hot nail into your bones over and over.

"Stickers in your yard hurt 10 times worse than a nonvenomous snake bite."

Want More on Snakes?

If you are interested in snakes and want to learn more about them, there are herpetological meetings and lots of internet resources.

snake from Department of Biology is popular at Arts & Sciences Day 2018, TTU photo by Toni Salama"There are a lot of Facebook pages where you can take a picture of a snake, post it and they'll get back to you in minutes, telling you what kind of snake it is and whether it's dangerous," Lee said.

And since nature is for everybody, he encourages anyone who is interested in snakes to learn more.

"I know a musician in Abilene who just looks for snakes in his free time," Lee said. "It's like fishing—like a weird fishing.

"People just have to make sure they can tell the difference and not put themselves in harm's way. We always tell people, if you don't know what a snake is, it's best to leave it alone. But snakes don't have to be scary."

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