Quick Facts: Snakes
The Serpent World
Snake, a messenger of doom for the uninformed; on the flip side, one of the most magnificent wonders of nature. From ancient myths and folklore to documentaries and motion pictures, snakes have always been a much talked-about phenomenon and a strong center of attention for reptile enthusiasts.
Mythologically, the snake is said to be one of the first reptiles on planet Earth. The mythological name for a snake is serpent, a term that comes from Old French and means "to creep." Fossil evidence reveals that modern snakes evolved from ancient lizards, and their rise coincides with the emergence of mammals.
These cold-blooded creatures not only don an air of mystery and uncertainty in their appearance, but their very existence remains an unsolved puzzle. As many as 2,900 species of serpents are known to wriggle in every corner on the Earth, except for Antarctica. They abound in all kinds of land terrains, and as you will see, some even took to the open ocean.
How Snakes Are Grouped
For most people, these many snakes could only mean a cauldron of deadly venom. But believe it or not, most types of snakes are non-venomous. Furthermore, snakes that possess venom use it to kill and subdue their prey, and less commonly for self-defense. It's the venomous kind that has created a bad name for all snakes, which results in thousands of snakes being killed for no reason other than their frightful appearance.
Scientists sort all these serpents into 18 families, and there are venomous snakes in many of them. Three of the most prominent families are the Elapids, the Viperids, and the Colubrids. In this guide we'll meet the major families in detail, then run through every remaining family so you can see the full, astonishing variety, from snakes longer than a school bus to ones barely longer than your finger.
How Snake Venom Works
A venomous snake uses fangs in its mouth to either kill or immobilize its prey, injecting venom and modified saliva through them. But not all venom is the same, different families use different "weapons," and the kind of fang a snake has tells you a lot about how it hunts.
Neurotoxic venom attacks the nervous system, jamming the signals between the brain and the muscles. This is the venom of the elapids (cobras, mambas, and sea snakes) and it is generally more dangerous than viper venom. Proteolytic venom, used by the vipers, is loaded with proteases, protein-degrading enzymes that break down flesh. A proteolytic bite causes intense pain, swelling, internal bleeding, problems with blood clotting, and in serious cases tissue death (necrosis), though it is not always fatal.
Fangs come in three main styles. Elapids have short, fixed front fangs that never fold. Vipers have long, hinged front fangs that fold back against the roof of the mouth and swing forward to strike. And colubrids are rear-fanged, their grooved fangs sit at the back of the upper jaw, so they usually have to chew venom into a wound, which makes a fast, dangerous bite less likely (but not impossible).
Elapidae (Elapids)
The Elapidae family comprises the most venomous species of snakes in the world. These snakes (elapids) are mostly found in the tropical and subtropical regions of the world. An important characteristic feature of the elapids is their fixed, hollow fangs, which are used to inject venom. There is almost no visible distinction between the head and the neck. Their venom is neurotoxic, which causes severe damage to nervous tissues, and thus it can be potentially deadly. Elapid lengths range from just 18 centimeters up to 5 or 6 meters, and there are 213 species in this family.
King Cobra (Ophiophagus hannah)
The longest venomous snake in the world, the King Cobra can reach lengths of up to 5.5 m (18 ft). Its neurotoxic venom is powerful enough to bring down an elephant. It is uniquely ophiophagous (a snake-eater) feeding almost entirely on other snakes, and it is the only snake known to build a nest for its eggs.
Other well-known elapids include:
- Black Mamba
- Indian Cobra
- Cape Cobra
- Green Mamba
- Egyptian Cobra
- Red Spitting Cobra
- Mozambique Spitting Cobra
- Kraits
- North American Coral Snake
- Australian Copperheads
- Inland Taipan (most venomous land snake in the world)
Viperidae (Vipers)
The next important family of venomous snakes is Viperidae. Snakes in this family (vipers) are known for their long, hinged hollow fangs. Unlike the elapids, which have fixed fangs, vipers have fangs that can retract and extend. When inactive, these fangs stay folded back against the roof of the snake's mouth. When the mouth opens, the fangs extend and get into a biting position, allowing the viper to penetrate deep into its prey. Vipers are found almost everywhere in the world except Madagascar, New Zealand, Hawaii, and Australia, and there are four sub-families: the Azemiopinae, Viperinae, Crotalinae, and Causinae.
Rattlesnake (Crotalus spp.)
One of the most recognizable vipers, the rattlesnake is named for the hollow, interlocking segments at the tip of its tail that rattle as a warning. These pit vipers are native to the Americas and are well adapted to both desert and forest habitats.
Other commonly known vipers include:
- Copperheads
- Water Moccasin
- Bushmaster
- Fer-de-lance
- Russell's Viper
- Fea's Viper
- Saw-scaled Viper
- Temple Viper
- Death Adder
- Adders
- Gaboon Viper
- Rhinoceros Viper
Colubridae (Colubrids)
The Colubridae family comprises snakes (colubrids), most of which are non-venomous or possess venom that is too weak to cause any harm to human life. However, there are some exceptions, such as the boomslang and twig snake, whose bites have been reported to cause fatalities. Colubrids have their fangs located not at the front of the mouth but angled at the back. Hence, they are also noted as rear-fanged snakes. Unlike the elapids and vipers, the fangs of the colubrids are not hollow, but simply grooved to channel the venom when a bite is laid.
The family of colubrids is the largest family of snakes, and their bodies are completely covered with scales. The Queen snake of this family is non-venomous and grows no longer than 60 centimeters; it can be gray, dark brown, or olive in color. The Common Keelback is another non-venomous colubrid, found near drains, ponds, and drainage systems, and it feeds mainly on frogs and small fish. Other common examples include:
- Scarlet Snake
- Corn Snake
- Bull Snake
- Desert Kingsnake
- California Kingsnake
- Western Coachwhip
- Racers
- Rough Green Snake
- Ribbon Snake
- Garter Snake
- Smooth Snake
- Water Snake
- Mussurana
- Hognose Snake
- Red Milk Snake
- Gray-banded Kingsnake
- King Ratsnake
- Baird's Rat Snake
- Black Rat Snake
- Mangrove Snake
- Vine Snake
- Tree Snake
Boidae (Boas)
This family comprises non-venomous but big and powerful constrictors, which can swallow a fully-grown buck apart from other large animals! These snakes rely on their strength to suffocate their prey, unlike the venomous ones which use venom as their primary weapon. They do not have fangs but rows of teeth in their upper and lower jaws, and they can stretch their jaws very wide. Boas are found in Asia, Europe, the Americas, Pacific islands, and Africa, and there are 43 species in this family.
It is quite interesting to know how these large reptiles kill their prey. When they coil around their prey, they seem to tighten their grip every time the prey breathes out. Furthermore, they also know when it's time to stop working on their "death-squeeze." Scientists say snakes can sense their prey's heartbeat and let go when it stops. Boas also give birth to live young instead of laying eggs.
Anaconda (Eunectes spp.)
The Green Anaconda is the heaviest snake in the world, capable of reaching over 8 m (26 ft) in length and weighing up to 250 kg (550 lbs). A semi-aquatic resident of South America's river systems, it hunts from the water, ambushing prey as large as deer and caiman.
Other popular Boidae members include:
- Boa Constrictor
- Emerald Tree Boa
- Rosy Boa
- Yellow Snake
Pythonidae (Pythons)
Similar to the Boidae family, the Pythonidae family also comprises large non-venomous snakes, which kill their prey by constriction. These ancient ambush predators hunt patiently and kill by constriction and induced asphyxiation, just like their cousins the boas. Most people easily confuse pythons and boas. While they are similar-looking and have almost the same feeding habits, there are certain characteristic features that set them apart. Pythons are oviparous (egg-laying) reptiles, while most boas give birth to live young (ovoviviparous) ones.
The geographical distribution of pythons is different from or less extensive than that of boas. They are found in Africa, throughout the Indian subcontinent, China, Hong Kong, the Nicobar Islands, Myanmar, the Philippines, and Indonesia. Common examples of pythons include:
- Reticulated Python
- Burmese Python
- The African Rock Python
- Green Tree Python
- White-lipped Python
- Ball Python
- Carpet Python
Hydrophiidae (Sea Snakes)
Hydrophiidae could be a subfamily of Elapidae according to some taxonomists. The family comprises sea snakes, which are extremely venomous but account for rare human encounters. These sea snakes are closely related to the cobra and grow to about 2 meters in length. There are about 50 species, and almost all of them are venomous. Their short, hollow fangs sit near the front of the upper jaw, and their venom contains neurotoxins and myotoxins, chemicals that attack the nerves and muscles. A fatal dose can be as little as 1.5 milligrams. Their venom is considered to be more potent than that of land snakes. This family can be further subdivided into the Hydrophiinae and Laticaudinae. Note that the association of Hydrophiidae to Elapidae is an inconclusive subject.
Some taxonomists consider it to be a subfamily of the Elapidae, while some continue regarding it as a different species of venomous snakes altogether. Common examples in this family include:
- Belcher's Sea Snake
- Spiny-headed Sea Snake
- Olive Sea Snake
- Spiny-tailed Sea Snake
- Turtlehead Sea Snake
- Beaked Sea Snake
- Jerdon's Sea Snake
- Yellow-bellied Sea Snake
- Yellow-lipped Sea Krait
- The Arabian Gulf Sea Snake
Frequently Asked Questions
How many types of snakes are there?
There are around 2,900 known species of snakes, grouped into 18 families that range from giant boas and pythons to tiny burrowing thread snakes.
Are most snakes venomous?
No. The large majority of snakes are non-venomous. Only some families, such as the Elapidae (cobras and mambas) and Viperidae (vipers and rattlesnakes), contain dangerously venomous species.
What is the longest snake in the world?
The reticulated python, a member of the Pythonidae family, is the longest snake and the longest reptile on Earth, it can grow to more than 28 feet.
What is the smallest snake in the world?
The Barbados threadsnake (Leptotyphlops carlae), found in the Caribbean, is the smallest snake in the world at a maximum length of about 4.09 inches.
The Other Snake Families
Beyond the famous six, the remaining families show just how varied snakes really are, from giant tree-climbers to burrowers barely longer than your finger. Here is a field-guide tour of the rest of the 18 families.
Acrochordidae Nonvenomous
These ancient aquatic snakes extend their domain from western India and parts of Sri Lanka all the way to Indonesia, Australia, New Guinea, and the Solomon Islands. Members include File snakes, Wart snakes, Java wart snakes, and Dogface snakes. They all have baggy skin with pyramidal scale patterns and range in size from more than half a meter to about 2.43 meters. They hunt fish in streams, rivers, and estuaries.
Aniliidae Nonvenomous
The Aniliidae family consists of only a single species: the pipe snake, also called the false coral snake or Anilius scytale. Found in South America, it has a cylindrical body with bright red and black bands and prominent head scales. It preys on fish, lizards, frogs, insects, and burrowing amphibians. It still has a vestigial pelvic girdle, a leftover carried forward from its lizard ancestry.
One interesting feature of the Aniliidae family is its ovoviviparity: embryos develop within eggs while they are still inside the snake's body and are born live, unlike other snakes whose egg embryos develop outside and whose young hatch outside.
Anomochilidae Nonvenomous
This family includes Leonard's pipe snake, Weber's pipe snake, and the mountain pipe snake. They are found in Malaysia, Indonesia, and Borneo. All three have small heads with symmetrical shields, small eyes, smooth scales, and short, blunt tails.
Atractaspididae Some venomous
Concentrated primarily in Africa and the Middle East, this family includes 64 different species, among them the Cameroon racer, Mole viper, Stiletto snake, Natal black snake, and burrowing asps. Most are small and harmless, but a few are capable of causing tissue necrosis with a venom sting. This family is surrounded by scientific controversy, many species were originally placed in other families, and its boundaries are still debated.
Bolyeriidae Nonvenomous
Endemic to Mauritius, this family has two species, one of which is already extinct. The only surviving species is the Round Island Boa. It can grow to a length of 5 feet and has keeled scales with a dark brown back, and it preys mostly on skinks and geckos. Amazingly, its dark brown color changes to a lighter shade over the course of a day, aided by an ingenious system of polychromatic cells.
Cylindrophiidae Nonvenomous
This family is made up of 8 species of burrowing snakes, found in China, New Guinea, Sri Lanka, Thailand, Myanmar, Vietnam, and Cambodia. It includes the red-tailed pipe snake, found all over Asia, and the island pipe snake of Indonesia. You can identify them by their black and white bellies, their cylindrical bodies with smooth back scales, and their short tails.
Loxocemidae Nonvenomous
This family consists of a single species, the Mexican python. It grows to a maximum length of 1.57 meters and has a muscular body, small eyes, and a narrow head, identified by its dark color and white scales. It is found throughout Mexico and along the Mexican Pacific.
Tropidophiinae — Dwarf Boas Nonvenomous
Localized in Brazil, the West Indies, and Mexico, the Dwarf Boas grow to only about 2 feet in length. They are nocturnal and mostly land-dwelling, with a peculiar color-changing ability. When threatened, these burrowing snakes use two surprising defense tricks: curling up into a compact ball, or bleeding from their eyes, mouth, and nostrils to scare off predators.
Uropeltidae — Shield-tails Nonvenomous
Endemic to Sri Lanka, this family consists of 47 non-venomous species. These land-dwelling snakes grow from 20 cm to 75 cm and are expert diggers, burrowing through the soil to create shelters for themselves. They feed on earthworms and other small organisms. Their bodies are cylindrical with smooth scales, and like boas they give birth to live young, being ovoviviparous in nature.
Xenopeltidae — Sunbeam Snakes Nonvenomous
Consisting of just two species (the Sunbeam snake and its cousin) this family is found in China, Vietnam, Southeast Asia, and Indonesia. The snake gets its name from its most eye-catching feature: iridescent, highly polished scales that shimmer with rainbow colors in the light. These non-venomous snakes grow up to 3 feet long. They are a fossorial species that inhabits forest slopes and kills prey by constriction.
Anomalepididae — Dawn Blind Snakes Nonvenomous
Also known as dawn blind or primitive blind snakes, these small burrowing snakes are endemic to South and Central America, with 15 known species. They have blunt heads and blunt tails, and they spend almost all of their time underground. Because they so rarely need to see, their eyes have become tiny, vestigial organs.
Leptotyphlopidae — Thread Snakes Nonvenomous
Thread snakes are a family of 90 burrowing snake species found throughout Asia, Africa, and America. Their average maximum body length is about 30 cm. They have cylindrical bodies, small flat heads, and very smooth, polished scales. This oviparous species has an average length of only 10 cm, with the offspring measuring just a single centimeter! These tiny snakes feed on termites, ants, and other insects.
Typhlopidae — Blind Snakes Nonvenomous
Consisting of 203 species, the Typhlopidae family is native to Asia, Africa, and North, Central, and South America. These insect-feeding blind snakes are very small and spend most of their time in burrows. Grant's blind snake, Jerdon's worm snake, and the Puerto Rican wetland blind snake are some of the species in this family.
Take the Snake Families Quiz!
9 quick questions. Find out how much you really know about snake families, their venom, and the record-breakers.
Venomous Snakes in Pictures
Now enjoy pictures of some of the most well-known venomous snakes in the world, eight marquee species from across the venomous families.
Black Mamba
Dendroaspis polylepis
Africa's most feared elapid, the black mamba is the fastest snake on land, capable of reaching 12 mph (20 km/h) in short bursts. Despite its name, its skin is olive to gray; "black" refers to the dark inside of its mouth, which it displays as a warning.
King Cobra
Ophiophagus hannah
The longest venomous snake in the world, king cobras can reach up to 18 feet (5.5 m). They are uniquely ophiophagous (snake-eaters) and are the only snake species known to build a nest for their eggs.
Indian Cobra
Naja naja
One of the most iconic snakes in Asia, the Indian cobra is renowned for its wide hood, which it spreads when threatened. It features prominently in traditional snake-charming performances and is revered in Hindu mythology.
Coral Snake
Micrurus fulvius tenere
Bright red, yellow, and black banding makes the North American coral snake one of the most visually striking elapids. The classic rhyme for telling it apart from harmless mimics: "Red touches yellow, kill a fellow; red touches black, friend of Jack."
Western Diamondback Rattlesnake
Crotalus atrox
The western diamondback is one of North America's most encountered venomous snakes. Its iconic rattle (made of keratin segments at the tail tip) serves as a warning signal, though it does not always rattle before striking.
Puff Adder
Bitis arietans
Responsible for more snakebite deaths in Africa than any other species, the puff adder is a master of camouflage. It puffs up its body and hisses loudly when threatened, and it can strike sideways as well as forward.
Gaboon Viper
Bitis gabonica
The Gaboon viper holds the record for the longest fangs of any venomous snake, up to 2 inches (5 cm). Its geometric brown-and-tan patterning provides near-perfect camouflage in the leaf litter of African rainforest floors.
Fer-de-Lance
Bothrops asper
The fer-de-lance is the most medically significant venomous snake in Central and South America. A large pit viper, its name is French for "spearhead", a reference to the distinctive triangular shape of its head.
More Venomous Species
The gallery above shows eight of the most iconic species. Here are more named venomous snakes, with their scientific names:
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- Cape Cobra, Naja nivea
- Copperhead, Agkistrodon contortrix
- Mozambique Spitting Cobra, Naja mossambica
- Egyptian Cobra, Naja haje haje
- Red-Tailed Racer, Gonyosoma oxycephala
- Eastern Tiger Snake, Telescopus semiannulatus
- Common Adder, Vipera berus
- Timber Rattlesnake, Crotalus horridus
- Black-Tailed Rattlesnake, Crotalus molossus
- Mohave Rattlesnake, Crotalus scutulatus
- Water Moccasin, Agkistrodon piscivorus conanti
- Persian Horned Viper, Pseudocerastes persicus
- Eyelash Viper, Bothriechis schlegelii
- Rhinoceros Viper, Bitis nasicornis
Living Alongside Snakes
Snakes are some of the most intriguing creatures created out of the crucible of evolution. No man-made technology can match the amazing biological technology that naturally emerged in them. Although the majority of snakes are non-venomous, they suffer the fate of getting killed whenever humans perceive them as a threat. Even venomous snakes will mostly bite only in self-defense.
Although non-venomous snakes are harmless, even venomous snakes pose no threat to human beings, unless they are provoked. In fact, all creatures in the animal kingdom do not bear any grudge against mankind. If we give them their space and let them be, they do not have any reason to reciprocate this feeling! We share a kinship with all life forms on Earth and must learn to share our world with them.
So don't fear a snake the next time you see one. Be careful, but avoid reacting violently and killing the poor thing, it's only looking for some food or shelter. And one more thing: stop buying handbags and other objects made of snakeskin, which is one way of stopping the poaching of these magnificent slithering creatures. Want to keep exploring? Meet the record-breakers in our guide to the biggest snake in the world, or learn the warning signs with our look at the most aggressive snake.
Glossary
| Word | What it means |
|---|---|
| Neurotoxic | Describes a venom that attacks the nervous system, disrupting the signals between the brain and the muscles, potentially affecting the ability to breathe. Elapid venom (cobras, mambas, sea snakes) is neurotoxic. |
| Proteases | Protein-degrading enzymes found in viper venom. They break down tissue and cause intense pain, swelling, internal bleeding, and damage to the blood's clotting system. |
| Constriction | The hunting method used by boas and pythons: the snake coils around its prey and tightens its grip each time the prey exhales, until the heart stops. |
| Ophiophagous | Literally "snake-eating." The king cobra is the most famous ophiophagous species, feeding almost entirely on other snakes. |
| Oviparous | Egg-laying. Pythons are oviparous, they lay eggs and (unlike most reptiles) often coil around the clutch to keep it warm. |
| Ovoviviparous | Producing live young from eggs that hatch inside the mother's body. Most boas, dwarf boas, and shield-tail snakes are ovoviviparous. |
| Rear-fanged | A fang arrangement where the grooved teeth sit towards the back of the upper jaw, rather than at the front. Most colubrids are rear-fanged. |
| Myotoxin | A toxin that damages muscle tissue. Sea snake venom contains both neurotoxins and myotoxins, making it especially potent. |
Fun fact for today!As many as 2,900 species of snakes are known to exist on Earth, and most of them are completely non-venomous!