The World’s deadliest snakes


The King Cobras in the Snake Park at Bangkok are not defanged but milked for extracting venom, and making antivenin. I used to visit the Park, frequently when I lived in Bangkok in the late fifties and  sixties, to witness this procedure, out of my own curiosity. (These days antivenin is produced in most countries for almost all species of snakes).

The venom is injected into the blood stream of a horse gradually, till the horse becomes immune to the venom and develops antibodies. Blood drawn from the horse consists of antibodies as well as other useless proteins. Only the antibodies which bind to and neutralize the circulating venom in a victim’s body constitute the antivenin.

The other useless protein which exists in addition to the antibodies would have to be discarded, as it produces a nearly fatal allergic response known as anaphylactic shock.

The snake-bite victim’s immune system recognizes the protein as a “foreign body”. Even before administering the pure antivenin, a skin test has to be performed on the victim to see whether the antivenin itself is acceptable to the victim. It is a question of choice between the life-saving benefit of the antivenin or potentially fatal reaction and certain death or amputation from the snakebite.

For each species of snake, the antivenin to be administered has to be tailor-made. The antivenin meant for the cobra will act only when it is given to a person bitten by a cobra and not by any other snake. The injection of antivenin and that too fairly quickly, is the only cure for snakebite. All other remedies are based on superstition and quackery.

In order to allow a quick estimate of the chance of recovery of poisoned victims, scientists have devised systems of toxicity on six commonly used measures (such as a few grams injected in a snake bite or a chemical swallowed ) and on the assumption that the victim is a 150-pound man. If less than seven drops can kill a man, they are rated class “6” (or super toxic). If the toxicity is extrapolated, snake venom which directly enters the bloodstream of the victim can prove to be more lethal in a shorter time than the deadliest bacterial, viral and chemical toxins.

There is another parameter by which Snake venom strength is measured using the LD50 (Lethal Dose 50%) test. It involves dosing several groups of animals with a poisonous substance either by mouth (force-feeding), by injection, via the skin or by inhalation. Animals used have included mice, ( the largest numbers) birds fish monkeys dogs cats and rabbits. The finishing point of the test is when half of the animals in the group have died. The amount of test substance that kills half the animals gives the LD50 figure. LD50 figures are used, in theory, to indicate the standard toxicity value for each kind of venom. The lowest figure represents highest toxicity.

This test has many shortcomings.  It  has been regarded  as “crude and unscientific”. LD50 figures for the same specimen of venom and  the same strength,  can vary enormously according to the strain , gender age, species,  and even diet of the animals species, used in the tests. There have been confusing and conflicting results.  For example In one survey, the LD50 figures for the same venom tested by two different laboratories, varied by three to eleven-fold). Unfortunately, Herpetologists do not as yet have a  a more accurate or humane test.  Another complication is that the test has to be repeated on more groups of animals and on a variety of species, so that an average LD50 figure can be obtained. The LD50 figure that is used to measure relative toxicities of various snake venoms is conducted using mice. This means the data is not  particularly accurate for estimateing how lethal a snake bite to a human would be. Using the LD50 test for estimating the danger of a particular species to humans is obvoiusly flawed . The current rank for the World’s deadliest snake cannot be assigned based on the LD50 figure!

The King Cobra is the largest venomous snake in the world, though not the deadliest. Its habitat is the vegetation stretching from the rural areas of Thailand and Southern China, to the Philippines, and parts of India. Herpetologists do not regard the king cobra as a cobra.

This misleading sobriquet has been given by ordinary people, as the huge snake can grow as long as 18 feet, stand up, raise and spread its head like the hood of a cobra. King cobras are usually found in pairs, which has given rise to the baseless and superstitious belief that a person who kills a king cobra will be hunted down and bitten to death by its mate in revenge.

The distinction of being the deadliest snake in the world had long belonged to the 50 kinds of sea snakes of Australia whose venom was considered more than 50 times as deadly as that of the King Cobra. However, the extremely venomous Australian Inland Taipan whose venom leads to death in a few minutes is now being regarded by many herpetologists as the deadliest snake in the world.

An Inland Taipan can grow to 13 feet in length.  These are usually found  in steppe climate region and They are extremely lethal and kill anything on its way by using their toxin. The death rates of humans are comparatively less, since they are shy and do not attack people  unless provoked. They usually try to escape from humans.  But the unlucky individual that crosses its path, and is bitten suffers the agonies  of hell before dying, and that too within 30 minutes. A single bite of the Inland Taipan , contains 110mg of venom that is capable of paralysing and killing up to 250,000 mice or 12,000 Guinea pigs or 100 humans. Common symptoms include paralysis respiratory failure and cardiac arrest eventually leading to the death of the victim.

We next come to the aggressive Mambas (Black as well as Green) of Africa whose lethal bites result in death within half an hour.  The Black Mamba is the longest venomous snake on earth after the King Cobra. It is found generally in South Africa, and South Central Africa, and is commonly referred as the “Kiss of Death”. They deliver enormous quantity of venom with just a single bite and have the capability to regenerate venom within hours after the encounter. The Black Mamba is very alert ,and  very aggressive, and is also one of the fastest land snakes. The toxin is highly lethal and when injected into the victim can trigger symptoms like nausea, blood clots, neurotoxicity and cardiac arrest, resulting in death.

In Africa the  Black Mamba has a reputation similar to that of the Indian cobra. It  travels faster, is much more aggressive and strikes with lightning speed, injecting a large quantity of venom that is unquestionably fatal, and gives the victim no chance for survival. As in the case of the king cobra, stories are told of a Black Mamba taking revenge for the death of its mate. The Black Mamba’s reputation as a savage killer is entrenched in the African psyche from childhood.

There is divergence of opinion among herpetologists, many of them holding the view that the Black Mamba of Africa is deadlier than even the Inland Taipan. The controversy will go on until a foolproof test is discovered.( having spent 8 years in Africa, and heard harrowing tales of the Black Mamba, over camp fires, my vote goes to the Black Mamba ! ) There is also in Africa a snake called the Boomslang, which almost looks like a quiet and lethargic pet but is nevertheless extremely poisonous.

The Cobras and the  Vipers come next in line. The Cobras are found in a vast geographical region stretching from the warm regions of Africa, including Egypt, to vast areas in Asia like India Burma and Thailand. The Cobra family of snakes may be regarded as the largest single group, if we include all the species of Cobras, the two main Mamba species ( the Black and the Green), and the three Taipan species( the Inland and the  the two Coastal Taipan subspecies).

The Asp, with whose bite Cleopatra ended her life in Shakespeare’s great play, and which is found throughout large parts of Africa belongs to the Cobra family; so also the Spitting Cobra, an aggressive Cobra, found throughout Africa which ejects venom at a victim’s eyes from a distance of up to seven feet, causing temporary or permanent blindness unless promptly washed out. The sprayed venom is harmless to unbroken skin, though if the snake does bite on rare occasions, the venom can prove fatal.

In India the Cobra is the stuff of mythology, folklore, and even cinema. There are festivals devoted to the worship of the cobra involving pouring of honey and milk over pits believed to be places where cobras reside. Special offerings are made to appease the cobra God. Movies are made in which Cobras play a major role- there are movies in which the heroine gets transformed into a Cobra at night and regains her human form in the morning after causing havoc mainly directed against the villain who tries to sexually exploit her and manipulate her behaviour by trying to  hypnotise her in vain. The hero gains the affection  of the heroine in the end!

There is a misconception that the Indian snake charmers can make a cobra swing its hood to a melodious tune on a wind instrument, but actually the snake integrates them to the ground vibrations it feels and sways its head in a manner that makes us believe it is enjoying the music.

Pit vipers are  or a subfamily of venomous Vipers. They are  found in Eurasia and the America’s. Pit vipers have heat a  sensing mechanism- a pit organ between the eye and the nostril, on both sides of the head, which  enable them to locate their prey. Major members of the large family of Vipers (160 species) are the lethal Gaboon viper of Africa found in the rain forests of Africa, the deadly deadly  Fer de lance (found in Mexico and South America) the Wutu (a type of Pit viper, found in Brazil, Uruguay, Paraguay and Argentina), the venomous Russell’s viper found from southern China to Indonesia and Sri Lanka and the Adders found throughout Europe and Asia.

Yet another deadly snake is the Rattlesnake of the Viper family found in North America, Mexico and South America. In terms of toxicity, it is at a much lower rung than all the very deadly snakes mentioned above. Its tail moves producing a rattling sound, before it strikes.

According to Sir David Attenborough, the world’s most famous animal watcher, the Rattlesnake has to be regarded as the most “efficient” snake in the world, because of the amount of venom it injects in a single bite – just sufficient to kill its chosen victim, in contrast to other snakes, particularly the King Cobra, which delivers in a single bite enough venom to kill 20 people.

One species of rattlesnake is the amazing “sidewinder”, which lives in the deserts in America and which is the only snake in the world that moves sideways in an extremely strange but aesthetic manner. At any given instant only two points on the underside of the snake maintain contact with the desert sand to protect it from the scorching heat of the sand.

In American homes when the conversation veers round to poisonous snakes, it is the Rattlesnake t.hat is discussed in a manner similar to the cobra in Indian living rooms. But a curious fact is, much as it is feared, Americans regard rattlesnake meat as a delicacy.

Herpetologist Romulus Whitaker, who lives in Chennai, takes the help of the snake-catchers, the tribal people Irulas of Tamil Nadu and Andhra Pradesh for his works on snakes. His contribution to herpetology in our country is enormous. Unless there are more dedicated people like Romulus Whitaker, it would not be possible for India to make further progress in the field of herpetology -something this country needs badly, considering that every year at least 50,000 people die due to snake bite.

Extremely deadly snakes are found in every corner of Earth. The only place on the planet where they are not found is Ireland – a strange Zoological oddity – a boon for the people of Ireland but a matter of scientific curiosity for biologists. No wonder the famous writer of fiction Jeffrey Archer wrote an interesting short story ‘There are No Snakes in Ireland’ in his collection ‘Twelve Red Herrings’.


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