All snakes have teeth, but poisonous, venomous snakes also have large hollow fangs for dispensing poison, which is held in a small sac on the snake's head behind its eyes. Some poisonous snakes have fangs so large that the fangs fold back into their mouths to prevent them from biting themselves. Of the venomous snakes in the viper family, only rattlesnakes have the characteristic rattle on the end of its tail. Baby rattlesnakes are born without rattles, and some rattlesnakes can also lose their rattles. Contrary to common belief, the rattles on rattlesnakes do not indicate the snake's age, but rather how many times it has shed its skin.
TL;DR (Too Long; Didn't Read)
Most snakes avoid confrontations with humans, but if you come across a snake in the wild and are unsure of its threat – you can't tell if it's poisonous or not – freeze and then slowly step backward before moving away, as rattlesnakes can bite from a coiled position at least one-third to one-half of their body length or farther.
Main Differences Between Poisonous and Non Poisonous Snakes
All poisonous snakes have an angular, wedge-shaped head, except for the red, black and yellow-banded coral snake that populates the Carolinas, Florida, Georgia, Alabama, Louisiana and Mississippi. Non poisonous snakes typically have long, slender bodies and vertical heads, though some non poisonous king and garden snakes can grow quite thick. Poisonous snake eyes have vertical, cat-eye slits for pupils instead of the round ones found on non venomous snakes. Of the poisonous snakes, the coral snake is the only round-pupil snake.
Vipers tend to have a smooth cap on their head between their eyes to their nose. Non poisonous snakes have longer, vertical heads and a smooth cap that extends far beyond the round-pupil eyes to their nose. The coral snake, again, is an exception and has that larger cap. On the underside of viper tails, you'll find undivided scales compared with non venomous snakes.
Poisonous and Non Poisonous Snakes List
The North American continent serves as home to a variety of poisonous and non poisonous snakes. In the poisonous category, the first group consists of snakes from the Elapidae family, including the western and eastern coral snakes and the yellowbelly sea snake, all of which inhabit humid, subtropical areas. Coral snakes mostly feed on other snakes, but despite their innocuous size and appearance, coral snake venom is deadly.
Other venomous snakes in North America include the cottonmouth, copperhead, the sidewinder and multiple different rattlesnakes, including the eastern and western diamondback and the timber rattlesnake known as Crotalus horridus. Vipers belong to the Viperidae family, known as pit vipers for a distinctive small angular pit that appears slightly below the eye and between the nostril. Of all the rattlesnakes in the U.S., the Mojave rattlesnake has the most potent venom.
The list of non poisonous snakes is longer because it includes a variety of king, garden, garter, rat, ground, worm, water, shovelnose, hognose, corn, racer, banded and other basically harmless snakes from the Colubridae family with 2,000 different species worldwide. Snakes in the Boidae family – pythons and boas – are not poisonous, but still dangerous because they kill their prey through constriction and are known as the world's giant snakes. In North America, there are only two native snakes in this family: the Rosy and Rubber boa, though many other invasive pythons and boas may exist in the wild because of people who raised them at home before letting them loose in the wild when they grew too big to contain.
Venomous vs. Non Venomous Snakes
Non venomous snakes in the garden or yard often keep poisonous snakes away. Kingsnakes typically make meals of other snakes, and though they don't hunt them outright, will constrict and kill rattlesnakes, as kingsnakes are immune to the rattlesnake poison. Snakes don't make good pets because you must keep them in glass enclosures or aquarium-like containers, and snakes require live food like small mice, rodents and lizards as food. Copperhead snake bites account for the most of the venomous snake bites in the U.S., but their bite is not as toxic as those of the eastern and western diamondback rattlers, and seldom fatal.
Bitten in the Wild
Venomous snakes don't bite by default; they only bite humans as a defense mechanism, preferring to keep their venom for their prey. Some vipers might even dry-bite, without inserting venom into the skin. Snakes bite most people because people try to pick them up or capture them. When confronted in the wild, most venomous snakes, if given the chance, slither away to safety, as humans are more dangerous to them. If you or someone else gets bit by a poisonous snake, experts recommend that you:
- Remain calm; stay inactive to prevent the venom moving through your body.
- Get to a hospital or doctor immediately by ideally having someone else drive you.
- Loosen constricted or tight clothing.
- Check for shock. Have the bitten victim lay flat, feet elevated (if not bitten) and cover them with some blankets or clothes.
- Identify the snake if you can or take a picture of it to help doctors choose the right venom, but don't try to capture or kill the snake.
You should never make incisions over the snake bite, suck the poison from the wound using your mouth, constrict the flow of blood to the limbs or run after being bitten by a poisonous snake, and don't administer any medications without consulting a doctor.
- University of Pittsburgh: Snakes of North America
- Desert Research Institute: Rattlesnake Safety
- University of Georgia: Eastern Coral Snake (Micrurus Fulvius) - Venomous
- University of Kentucky: Snake Characteristics
- University of Nebraska-Lincoln: Midwestern Snakes Facts & Folklore
- Living Alongside Wildlife: Aging Rattlesnakes: Don't Bother Counting Their Rattles
About the Author
As a journalist and editor for several years, Laurie Brenner has covered many topics in her writings, but science is one of her first loves. Her stint as Manager of the California State Mining and Mineral Museum in California's gold country served to deepen her interest in science which she now fulfills by writing for online science websites. Brenner is also a published sci-fi author. She graduated from San Diego's Coleman College in 1972.