Snakes

National Geographic

10-06-2025

There are over 3,000 types of snakes in the world. They have wide distribution, living everywhere except in Antarctica, Iceland, Ireland, Greenland, and New Zealand. In the United States, snakes live in almost every state, except Alaska, Hawaii, and Maine.
About 600 species are venomous. Of those, only about 200 can kill or significantly wound a human.
Nonvenomous snakes, which range from harmless garter snakes to the not-so-harmless python, dispatch their victims by swallowing them alive or constricting them to death. Whether they kill by striking with venom or squeezing, nearly all snakes eat their food whole, in sometimes astoundingly large portions.
Almost all snakes are covered in scales. As reptiles, they're cold blooded and must regulate their body temperature externally. Scales serve several purposes: They trap moisture in arid climates and reduce friction as the snake moves. Several species of snakes are mostly scaleless, but even those have scales on their bellies.
Cultural significance of snakes
Throughout history, snakes have been important symbols in cultures across the globe. In ancient Egypt, people often associated snakes with royalty. The goddess Wadjet was depicted as a snake. Pharaohs wore head gear and held scepters topped with a uraeus, or the upright form of an Egyptian cobra.
Many East Asian cultures see snakes as symbols of immortality and renewal because they can shed their skin. The snake is also one of 12 animals that hold a spot on the Chinese zodiac and star in many folklore.
Snakes are also familiar creatures in Native American folk tales and traditions. The Hopi and Cherokee see snakes as connections to the Underworld that deserve reverence and respect.
How do snakes hunt?
Snakes eat all sorts of animals, from small mammals and small fish to larger prey up to three times larger than the width of their head.
They're able to swallow such large animals because their lower jaws unhinge from their upper jaws. Once in a snake's mouth, the prey is held in place by teeth that face inward, trapping it there.
Snakes hunt by flicking their forked tongues in different directions to smell their surroundings. That lets them know when danger—or food—is nearby.
Snakes have several other ways to detect a snack. Openings called pit holes in front of their eyes sense the heat given off by warm-blooded prey. Bones in their lower jaws pick up vibrations from rodents and other scurrying animals.
(Snakes gang up to hunt prey—a first)
Left: A green tree python (Morelia viridis) at the Riverside Zoo. Right: Speckled rattlesnake (Crotalus mitchellii) at the Arizona-Sonora Desert Museum. Photographs by Joel Sartore, National Geographic Photo Ark
Behavior and reproduction
About once a month snakes shed their skin, a process called ecdysis that makes room for growth and gets rid of parasites. They rub against a tree branch or other object, then slither out of their skin head first, leaving it discarded inside-out.
Most snakes lay eggs, but some species—like sea snakes—give birth to living young. Very few snakes pay any attention to their eggs, with the exception of pythons, which incubate their eggs.
(These are the rules of king cobra fight club—no venom allowed.)
Here's a fact to make ophidiophobes feel uneasy: Five species of snakes can fly.
Sea snakes
Most snakes live on land, but there are about 70 species of snakes that live mostly among the coral reefs in the Indian and Pacific oceans. These family elapidae sea snakes and their cousins, kraits, are some of the most venomous snakes that exist. The yellow bellied sea snake is one of the most venomous.
Most sea snakes pose little threat to humans because they're shy, gentle, and their fangs are too short to do much damage.
What to do if you see a snake in the wild
Experts say it's best to leave snakes alone and give them plenty of room. A rattlesnake (Crotalus) can lunge about two-thirds of its body weight. Most nonvenomous snakes will eventually glide out of the way.
If a snake doesn't move, experts say to wait it out or just turn back. Do not attempt to handle it or touch it with a stick. Rattlesnakes don't always rattle their tails in warning, so it's important to be extra careful.
(The key to protecting rattlesnakes from extinction? Clearing their name and reputation.)
Conservation status
There are nine IUCN Red List categories: Not Evaluated, Data Deficient, Least Concern, Near Threatened, Vulnerable, Endangered, Critically Endangered, Extinct in the Wild, and Extinct.
Roughly a hundred snake species are endangered, typically due to habitat loss from development. Of those endangered snakes, 17 percent are vipers.
Pythons 101 From unbelievably flexible jaws to rows of razor sharp teeth, a range of impressive features make the python one of nature's most formidable predators. Learn about ball, burmese, reticulated, and other types of pythons, what the snakes eat, where they live, and how a surprising feature might be a sign of legged ancestors.
What are the top 10 biggest snakes?
The 10 biggest snakes in the world are the African rock python (Python sebae), amethystine python (Simalia amethistina), black mamba (Dendroaspis polylepis), boa constrictor, Burmese python (Python bivittatus), green anaconda (Eunectes murinus), Indian python (Python molurus), king brown (Pseudechis australis), king cobra (Ophiophagus hannah), and reticulated python (Malayopython reticulatus).
—BBC Science Focus Magazine
What are the four most poisonous snakes? India has nearly 60 highly venomous snakes, including a few known as the 'Big Four.' They are the common krait, Russell's viper, saw-scaled viper, and spectacled cobra.The snake with the deadliest venom in the world is the western or inland taipan. These snakes live in arid and semi-arid regions of Australia. Taipan venom contains a mix of toxins that paralyze muscles, constrict breathing, and cause internal bleeding.
—Wildlife S.O.S. and Britannica
What will keep snakes away? There are many ways to deter snakes from entering your home or property. Discourage rodents by maintaining a tidy yard and patching any holes or cracks where animals can enter. Keep pet food stored indoors and consider fencing or concrete walls to provide a physical barrier to snakes.
Most experts don't recommend chemical repellents, which can be ineffective and harmful to others. Experts also discourage inhumane deterrents such as glue traps and ceramic eggs in chicken coops. —Utah State University
How dangerous are snakes? Of the 3,000 species of snakes in the world, only about 10 percent are venomous. Half of those have venom deadly enough to cause human fatalities.
—Rainforest Trust
This story originally published on January 25, 2019. It was updated on June 10, 2025.