World's Deadliest Snakes | Reptile Gardens | Rapid City | South Dakota

"Top 10" deadliest snake lists are very subjective. People often create lists based on the toxicity of snake venoms but generally do not to take into account the clinical ability to treat, or inability to treat, bites. Many of the world's most venomous snakes have venoms that are very straightforward and 'easy' to treat effectively with the proper anti venoms; Mamba bites are this way. However, other species that might fall far below the so-called 'Top 10' cause a clinical explosion of problems for which anti venoms are not very effective. Some rattlesnake bites are like this. There are still other people who derive their deadly snake lists from deaths in the countries they live in, study in, or that they are just fond of. All these points of view make for tremendous confusion in Top 10 lists. We feel it is far more interesting and important to list the most dangerous and deadly snakes in the world by region.

Toxicity: What does venom toxicity really mean and how is it calculated? Toxicity is determined by how much venom it takes to kill a test animal. It is tested via the "Lethal Dose for 50%” (LD50) method. That is, how much venom it takes to kill 50% of the test animals, normally mice. In determining an LD50 we must also discuss the route of injection. Subcutaneous (under the skin) bites are the most applicable to actual snakebites. Very large bites from Gaboon Vipers, Rhino Vipers, Crotalus or Rattlesnakes, and Bothrops or South American Lanceheads, also called Fer-de-lances, are about the only snakes capable of delivering an intra muscular (into the muscle) bite. Intravenous (in a vein) bites are extremely rare and very, very unfortunate, as most of those are rapidly fatal. Intra peritoneal (in the body cavity) bites are even more rare for humans. The LD50 method has its weaknesses. For instance, it has been found that some snake venoms have a more drastic - or less drastic - effect on a test animal than on a human.

It is important to keep in mind when discussing venomous snakes that the most deadly snake and the most dangerous snake can be two entirely different concepts. Some of the snakes with the most toxic venom, i.e., the most deadly, rarely bite people. In fact, the deadliest sea snakes are generally quite docile. And the Inland Taipan, the land snake with the deadliest venom has never killed anyone on record. On the other hand, the snakes that kill the most people (most dangerous) don't have venoms that would be at the top of any Top 10 list.

Snake We have devised what we call our DANGER QUOTIENT for each snake species. Our list will consist of the most dangerous snakes on each continent. The quotient is based on 5 critical factors, each with a maximum of 5 points.

Average adult size
Average venom yield
Toxicity of venom
Length of fangs
Typical disposition when cornered or threatened

Quotient numbers are based on a comparison of just the venomous snakes in that particular region; therefore you cannot look at - for instance - North America's numbers and compare them with Australia's.

Puff Adder (Bitis arietans) Puff Adders are cryptically colored snakes that grow to a very large size with a bad disposition, long fangs, and a dangerous venom. These snakes are also routinely found close to human habitation. They cause many human deaths as well as a very large morbidity rate in bite recipients. Many legs and arms need to be amputated due to the damage from this snake’s venom! DANGER QUOTIENT 19

Boomslang (Dispholidus typus) The Boomslang is the most venomous rear-fanged snake in the world. They have very long fangs and can open their mouths a full 180 degrees to bite. Famous herpetologist Karl P. Schmidt died 28 hours after a Boomslang bite. The day after the bite, he called in to say he felt well and would be in to work...2 hours before he, literally, dropped dead from the bite. DANGER QUOTIENT 13

Black Mamba (Dendroaspis polylepsis) These snakes are large, alert, and aggressive in their personal defense. With a very toxic venom supplied in large amounts, this is one of the most feared snakes on the African continent. DANGER QUOTIENT 20

Forrest Cobra (Naja melanolueca) This is a common species prone to stand and fight with a toxic venom, large size, but relatively average fang length. DANGER QUOTIENT 19

Egyptian Cobra (Naja haje) Another common species with toxic venom, fairly good-sized, an even temperament, and average fang length. They are commonly found in, and around, human habitation. DANGER QUOTIENT 16

Gaboon Viper (Bitis gabonica) Although their venom is not as toxic as many other African snakes, this species has enormous venom glands and the longest fangs of any snake in the world. It is very heavy-bodied and can strike with great force. Famed naturalist Marlin Perkins received a mild envenomation from a Gaboon and later said it felt like his insides were on fire. DANGER QUOTIENT 17

Saw-Scaled Viper (Echis carinatus) Saw-Scaled Vipers kill more people in Africa that all the other venomous African snakes combined. According to some researchers its venom is 5 times more toxic than that of the cobra and 16 more toxic than the Russell's Viper. Saw-Scaled Vipers are a small extremely irritable species of snake found close to human habitation. Sherman Minton, one of the world's pioneers in snake venom research and treatment once said it appears that humans are very susceptible to this snake’s venom and it could very well be the most venomous snake to humans! DANGER QUOTIENT 15

Saw-scaled viper (Echis carinatus) Saw-Scaled Vipers kill more people in Asia that all the other venomous Asian snakes combined. According to some researchers its venom is 5 times more toxic than that of the cobra and 16 more toxic than the Russell's Viper. Saw-Scaled Vipers are a small extremely irritable species of snake found close to human habitation. Sherman Minton, one of the worlds most pioneers into snake venom research and treatment once said that it appears that humans are very susceptible to this snakes venom and it could very well be the most venomous snake to humans! DANGER QUOTIENT 15

Russell’s viper (Daboia species) This snake is the leading cause of death in the country of Sri Lanka. Many snakes are known to produce little venom or no venom when biting defensively. However, the Russell’s Viper is well known for it's tenacity when defending itself and almost always delivers a lethal quantity of venom. DANGER QUOTIENT 20

King Cobra (Ophiophagus hannah) Although their venom is not nearly as toxic as many of the other snakes in Asia, the potential venom yield in a bite is phenomenal. These are the largest of all venomous snakes and are highly intelligent. It is said they can produce enough venom in a bite to kill an elephant. They do, however, have relatively short fangs and are not very aggressive unless defending a nest. DANGER QUOTIENT 19

Common Cobra (Naja naja ssp.) Cobras are considered to be the most common venomous snake in the most densely populated part of the world, which is South East Asia. Regarding snake bites in this region, many areas of this region have less than adequate medical facilities, traveling to the hospital from remote regions is difficult, many people seek out traditional medicine instead of hospitals, and finally, large numbers of people walk barefoot and work in cobra-rich environments, like rice paddies and other agriculture fields. All this combined with the very toxic venom of the Asiatic Cobras means 40,000 people die from cobra bites each year in this region. DANGER QUOTIENT 15

Malayan Krait (Bungarus candidus) Southeast Asia and Indonesia. 50% of the bites from this snake are fatal even with the use of antivenin treatment. This shy and retiring snake is most active at night so most bites occur when people are sleeping or walking on paths in the dark. Recently a well-known herpetologist was killed by a Krait after his native guide misidentified the snake. DANGER QUOTIENT 13

Beaked Sea Snake (Enhydrina schistosa) South Asian waters Arabian Sea to Coral Sea. Sea snakes are legendary for having deadly venom. At one time this species was considered to have the deadliest venom of any snake. However, current research shows this not to be the case, bites from this shy species are very rare. DANGER QUOTIENT 13

Fierce Snake or Inland Taipan (Oxyuranus microlepidotus) The most toxic venom of any snake, maximum yield recorded (for one bite) is 110mg. Which is enough to kill over 100 people or 250,000 mice. This snake, however, is rarely encountered, and there have been no recorded deaths from an inland bite. DANGER QUOTIENT 18
**These rare snakes are virtually unknown in collections outside of Australia, however, At Reptile Gardens, we have the only Inland Taipans outside of Australia other than one at the Moscow zoo and one in another European zoo.

Coastal Taipan (Oxyuranus scutellatus) The venom delivered in a single Taipan bite is enough to kill up to 12,000 guinea pigs. This is the largest venomous snake in Australia and is one of the only species known to give multiple bites AND deliver increased amounts of venom in subsequent bites. Before anti venom was available 100% of bites were fatal. They are alert snakes that are good at avoiding human contact. DANGER QUOTIENT 24

Papuan Taipan (Oxyuranus s. canni) This New Guinea species accounts for most of the snakebite deaths in the Papuan Gulf region. Venomous snakebite deaths are 100 times higher in New Guinea than in Australia due to quality and availability of treatment. They are similar to Australian coastal Taipan discussed above. DANGER QUOTIENT 24

Australian Brown Snake (Pseudonaja textilis) This is one of the most commonly encountered venomous snakes in Australia with a venom that is reputed to be the second most toxic in the world. They cause the most snakebite deaths in Australia. They are of average size, with small fangs but are fast and aggressive in personal defense. 1/14,000 of an ounce of this venom is enough to kill a person. DANGER QUOTIENT 15

Tiger Snake (Notechis scutatus) The legendary Tiger snake of Australia is a very aggressive snake with an extremely toxic venom and are relatively common within their range. This is another snake that was, prior to modern testing methods, considered to be the most deadly worldwide. DANGER QUOTIENT 17

King Brown Snake (Pseudechis austalis) This is one of the most widespread venomous snakes in Australia. One report states that the largest amount of venom ever extracted from a snake, 1300mg, came from a King Brown Snake. They can be large and aggressive but bites are relatively uncommon, although quite life-threatening when they occur due to the quantity of venom delivered and its effects. DANGER QUOTIENT 22

Death Adder (Acanthophis antarcticus) The Death Adder of Australia and New Guinea looks like a viper but is more closely related to the Cobra. A dosage of 10mg of Death Adder venom is enough to kill a human. A good sized Death Adder can deliver up to 180mg in a single bite. DANGER QUOTIENT 16

Barba Amarilla (Fer-de-Lance) (Bothrops asper) This is one of the scariest snakes on the planet, according to our Curator. These large aggressive snakes have long fangs, and lots of very toxic venom. Members of this genus are some of the only snakes that can, and regularly do, strike more than half their body length. DANGER QUOTIENT 24

Mexican West Coast Rattlesnake (Crotalus basiliscus) This very large, heavy-bodied snake has huge amounts of highly toxic venom, long fangs, and a temperament that makes them scary. DANGER QUOTIENT 20

Bushmaster (Lachesis sp.) Another big snake with lots of toxic venom and very long fangs. However, they are relatively docile most of the time. DANGER QUOTIENT 19

South American Rattlesnake (Cascabel) (Crotalus terrificus) An average sized rattler with very toxic venom, long fangs, and a fairly bad temperament. They have a smaller than average venom yield. Roughly 12% of the bites are fatal. DANGER QUOTIENT 18

Golden Lancehead (Bothrops insularis) Some researchers feel this snake has one of the deadliest of all snake venoms. They are relatively small snakes with low venom yield, decent sized fangs, but are a bit feisty and have a super toxic venom. DANGER QUOTIENT 17

Common Lancehead (Fer-de-Lance) (Bothrops atrox) Although not overly large, this snake maintains a slightly above average venom yield, which is relatively toxic, long fangs, and has the tendency to strike when approached. DANGER QUOTIENT 17

European Vipers (Vipera sp.)
There are several species of the common European viper. None of them are particularly toxic or dangerous. Bites are often cause for hospitalization but rarely, if ever, result in death.
DANGER QUOTIENT 11

Eastern Diamondback Rattlesnake (Crotalus adamanteus) This is the largest venomous snake in the US. It has huge venom glands, and relatively long fangs. Its venom is of above average toxicity, but it maintains a rather mild disposition for a rattlesnake. DANGER QUOTIENT 19

Western Diamondback Rattlesnake (Crotalus atrox) Another large snake with a higher than average venom yield and fang length, and an irascible disposition, although the venom is below average in toxicity. DANGER QUOTIENT 17

Mojave Rattlesnake (Crotalus scutatus) This rattlesnake has one of the most toxic venoms of all the rattlesnakes, slightly higher than average venom yield, and fang length, with a fairly excitable disposition. They are, however, relatively small. DANGER QUOTIENT 16

Prairie Rattlesnake (Crotalus viridis) Although it maintains a higher than average venom toxicity and fang length, coupled with a stand-and-fight disposition, and the widest striking range of all the rattlesnakes, its size and venom yield are below average. This is the snake that accounts for the largest number of venomous snakebites in the US. DANGER QUOTIENT 14

Timber Rattlesnake (Crotalus horridus) Slightly above average in all categories except for disposition, they are one of the meekest of all the rattlesnakes. DANGER QUOTIENT 14

Coral Snake (Micrurus fulvius) Coral Snakes have an extremely potent venom but are small, secretive, and relatively gentle. Some researchers consider them to be too small to deliver enough venom to kill a human. This is the only elapid (relative of the cobras and mambas) in the US. DANGER QUOTIENT 9

Throughout the world, it is estimated there are a minimum of 1 to 2 million annual snakebite "incidences”. This number includes bites by non-venomous species. Of that number, roughly 50,000 to 100,000 bites result in fatalities worldwide. The country with the largest number of annual snakebite deaths is the tiny island nation of Sri Lanka.

Each year in the United States there are approximately 1400 venomous snakebites, but generally only about 1 is fatal. In Australia, the country with the highest percentage of deadly snakes, just 3 to 4 people are killed by venomous snakes yearly.

There are innumerable combinations of variables that affect the outcome of a snake envenomation. The size, age, and health of both the snake and the person bitten are important factors. Body temperature, even mood, of a particular snake plus the toxicity and quantity of venom delivered by that snake can all make a very big difference in the outcome of the bite. Snakes have complete control over how much venom they inject anytime they bite. So one could get a “dry” bite, with no venom in it whatsoever, or a particularly annoyed snake might inject its maximum amount. Interestingly, studies have also shown that the toxicity of the venom in a particular snake can vary considerably from day to day.

The location of the bite is another consideration, along with route of injection, and even sensitivity and/or allergies of the person bitten. Adding the potential for a severe infection, and it is safe to say there are many variables that will affect the out come of a snake bite.

General statements regarding certain snakes having a neurotoxic venom (affecting the nervous system) and of others with a haemotoxic venom (affecting tissue and blood) are regularly discussed. There are actually more than two types of toxins and countless combinations of these. To name just a few, there are: myotoxins, cardiotoxins, haemotoxins, and neurotoxins. No snake possesses just one type of toxin. All snakes have a combination of them. It is this variable combination that makes reactions to bites from different species so different.

Venom is merely modified saliva, a combination of many different proteins and enzymes. Each one of these proteins and enzymes acts alone, and in combination with the others present. When one reacts with the other enzymes and proteins present, this causes an entirely new reaction. This repeats, one enzyme/protein reacts with another and another and another, ultimately resulting in a domino effect. Because of this chain reaction, many areas of the body are affected, becoming a clinical nightmare to treat.

Travelers and servicemen who have been to Southeast Asia frequently ask about the "100 pace snakes" (or 50 pacers or 1000 pacers, etc.) they heard so much about and feared while there. Various species of tree vipers from the genus Trimeresurus have been given this name. This reputed deadliness, however, is just a folk tale. These snakes have very mild venom and deaths from their bites are virtually unknown.

Closer to home, many people believe the Cottonmouth (Agkistrodon piscivorus) and the Copperhead (Agkistrodon) to be very deadly. Again, the truth is rather disappointing; they are not really very deadly at all. The maximum amount of venom a Cottonmouth can deliver is just barely enough to kill a single person if it can at all. The chances of a snake delivering its maximum venom in a bite are extremely unlikely. The Copperhead is even less deadly, even if untreated; a Copperhead bite causes death in considerably less than 1% of the bites. Again, keep in mind that these two snakes rarely deliver anything close to their maximum dosage.