Animals with Fangs: How Snakes, Spiders, and Vipers Deliver Venom
October 25, 2026
Animals with fangs have unsettled people for as long as people have told stories. Dragons, gargoyles, and demons are commonly drawn with prominent fangs, and fangs are one of the defining traits of vampires. The real animals behind the legends are less supernatural, but they are just as interesting.
A fang is a long, pointed tooth. Fangs and tusks are elongated canine or incisor teeth, and fangs deliver venom while tusks serve as defensive weapons. Vampire bats, which feed exclusively on blood, are one of the more famous fanged mammals. They also appear in our guide to animals with rabies.
This article looks at five fanged animals, starting with snakes and spiders in general and then narrowing to species that matter most to readers in the United States. It also covers the old-world common adder, which has a long history in European folklore.
1. Snake
Snakes are the animals most people think of first when they hear the word fang. Yet fangs are rarer than the reputation suggests. According to Discover Wildlife, only 725 of around 3,900 snake species are venomous, and only 250 of those can kill a human with one bite. Most snakes have teeth, but only the venomous ones have fangs.
Fang design varies a lot between snake families. Cobras, mambas, and kraits have fixed front fangs and typically neurotoxic venom. Vipers and pit vipers have long, hinged fangs, and their venom is often haemotoxic or cytotoxic, causing bleeding and tissue damage. Primitive back-fanged snakes inject venom through grooves in their teeth.
| Snake Group | Fang Type | Typical Venom Effect | Familiar Examples |
|---|---|---|---|
| Cobras, mambas, and kraits | Short, fixed, front-mounted | Nerve and breathing effects | King cobra, black mamba |
| Coral snakes | Small, fixed, front-mounted | Neurotoxic | Eastern coral snake |
| Vipers and pit vipers | Long, hinged, fold against the roof of the mouth | Bleeding and tissue damage | Rattlesnakes, copperheads, cottonmouths, adders |
| Back-fanged snakes | Grooved teeth at the rear of the jaw | Slow delivery, needs chewing | Several small rear-fanged species |
Hinged fangs are an engineering feat. They lie folded on the roof of the mouth until the jaw opens wide and the bone holding them rotates them into position. Because of the snake’s muscular elasticity, the fang tips at penetration average 112 percent further apart than their bases at rest.
Venom has a medical history too. In many countries, venomous snakes are caught and “milked,” and the venom is used to make antivenom that saves bite victims. Snakes also hunt with more than their mouths. Some use a flicking tongue to smell and track a bitten animal until it dies, a trait explored in our list of animals with long tongues.
Snakes have no limbs, so the mouth does the work that animals with claws do with their paws. In the United States, the venomous species include rattlesnakes, copperheads, and cottonmouths, which are pit vipers, plus the eastern and Texas coral snakes.
2. Spider
Spiders do not have teeth, so their “fangs” are a different structure. Spiders typically deliver venom with a bite from piercing, fang-like chelicerae. Strictly speaking, all spiders and scorpions have venom, though only a handful are dangerous to humans, according to Wikipedia’s list of venomous animals.
Size varies enormously. The Goliath birdeater (Theraphosa blondi), a South American tarantula, is the largest and heaviest tarantula, with fangs up to 2 inches long. Most spiders found in American homes have fangs far too small to break human skin.
Fang action separates the major spider groups. Tarantulas strike with fangs that stab downward. Most other spiders, including widows and recluses, use fangs that pinch toward each other.
- Tarantulas: Large and hairy, they live in the American Southwest and rarely bite people unless handled roughly.
- Widow spiders: The southern black widow (Latrodectus mactans) is the species most Americans picture, with potent venom delivered through small fangs.
- Recluse spiders: The brown recluse (Loxosceles reclusa) lives mainly in the central and south-central states and is shy by nature.
Spiders are also visual hunters. Jumping spiders in particular have large forward-facing eyes, which makes them a natural fit for our roundup of animals with big eyes.
3. Western Diamondback Rattlesnake
The western diamondback (Crotalus atrox) is the rattlesnake many Americans meet on desert trails. It lives across the Southwest, including Texas, Arizona, and New Mexico, and into northern Mexico. Its stout body and diamond-patterned back make it easy to recognize once you know what to look for.
Its fangs follow the standard pit viper plan. They fold back when the mouth is closed and swing forward when it opens, so the snake can strike and inject venom in a fraction of a second. For scale, Discover Wildlife reports that its eastern relative, the eastern diamondback (Crotalus adamanteus), weighs as much as 15.4 kg, has 1-inch fangs, and carries a hemotoxin that damages red blood cells and tissue.
Pro Tip: A rattle is a warning, not an invitation. Fortunately, you can hear this snake coming. If you hear one, stop moving, locate the sound, and back away slowly along your original path.
History has not been kind to the species. Rattlesnake roundups in Texas, a decades-old tradition, have centered on western diamondbacks. Conservation groups and many communities now question the practice, and some events have shifted to festivals that do not involve capturing wild snakes.
Important Note: This article is educational and is not medical advice. After any suspected venomous bite in the US, call 911 right away and keep the person calm and still. Poison Control is also available at 1-800-222-1222. Do not cut the wound or try to suck out venom.
4. Rattlesnake
Rattlesnakes are a New World group of pit vipers, divided into the genera Crotalus and Sistrurus. They range from southern Canada to South America, and the highest diversity is in the American Southwest and Mexico. The timber rattlesnake (Crotalus horridus) represents the family in the eastern United States.
Their fangs are the largest working parts of the snake’s defense. The fangs of vipers, which include rattlesnakes, are much longer than those of cobras and mambas. The fangs are changed periodically, and rattlesnakes shed theirs about every 60 days. A replacement fang usually waits behind the working one, so the snake is never without a weapon.
Rattlesnakes also carry real weight in American history. Colonial Americans adopted the coiled rattlesnake as a symbol of vigilance and resistance. The Gadsden flag, from 1775, still shows one above the words “Don’t Tread on Me.”
Many pit vipers, rattlesnakes among them, have amber or yellowish eyes with vertical pupils. For more on that look, see our guide to animals with yellow eyes. They are also part of the larger viper family, which you can browse alongside other animals that start with V.
5. Common Adder
The common adder (Vipera berus) is Europe’s best-known viper, and its history is tangled up with its name. The word adder was applied to different snakes because they look alike, even though they are not all related, according to Live Science and Utah State University snake biologist Alan Savitzky. Snakes in the genus Acanthophis are related to cobras but are called death adders because they resemble vipers.
American readers may know the name from another animal. The eastern hognose snake, sometimes called a puff adder, hisses and puffs its head like a cobra but then plays dead and almost never bites. It is nonvenomous and is not related to the venomous African puff adder.
The real adder is modest in size. According to Britannica, it reaches about 85 cm (33 inches), is usually gray to brown with a dark zigzag on the back, and eats frogs, young birds, and small mammals. It bears live young, with 6 to 20 born in August or early September. Its eyes are often a red-orange shade, so it also fits among the animals with red eyes.
Its fangs are the same hinged type seen in rattlesnakes. Like other vipers, the adder has hinged fangs that fold against the roof of the mouth, which lets them grow relatively long. Even so, its bite is rarely fatal to humans.
The adder’s range is remarkable. It is the northernmost snake in the world, reaching the Arctic Circle, and it is the only venomous snake found in Great Britain. In colder climates, adders hibernate for five to seven months over the winter.
Across all five animals, the pattern is consistent: fangs are tools for feeding first and self-defense second. Hinged viper fangs, fixed cobra fangs, and spider chelicerae each solve the same problem in a different way. For more fanged and non-fanged creatures to explore, browse our animals that start with S.