In certain forums on the web we find lists purporting to rank the most dangerous and/or venomous snakes in the world. Unfortunately one can take one's pick as there are a number - and none of them agree with each other.

How accurate are they? How long is a piece of string?

The criteria for judging the most dangerous snakes should be simple. In fact only one factor can legitimately be used - human deaths attributed to the specific species.

Contributing factors would be the distribution of the species, aggression, venom yield, toxicity of venom, habits of the snakes.

Obviously a fairly venomous species that is found in vast reaches of the earth will kill more humans than a violently venomous species known to live on only one inaccesible grassy knoll on an uninhabited Patagonian island.

However when all is said and done - the only accountable factor MUST be the body count of the species.

As to the most venomous we run into similar problems of definition. The effect of snake venom is measured in mouse units. The standard test is to measure how many standard sized mice a given weight/volume of venom will kill. From there an estimation and extrapolation is made to a standard 70 kg human male.

The problems inherent here are:

Fierce Snake
Australia's crop of highly venomous elapids feature high on many lists. Yet Australia has had, over the last 20 years, a confirmed mortality rate averaging less than 2 per annum and a guestimated maximum of 3.1 per annum. (These are people who die from snakebite in remote places and where medical science does not make a diagnoses).

This translates, roughly, to a mortality rate of 1:8 million per annum. Distributed roughly among 16 highly venomous snakes. Average per species thus is 1 fatality per snake species every 8 years. The vaunted "most venomous snake on earth" the Fierce Snake (Oxyuranus microlepidotus) has yet to be implicated in a single fatality. The range of the snake is small and the population extremely thin. So despite the fact that an average yield of venom from this snake can kill 250 000 rats, just how dangerous is it?

Russell's Viper
On the other hand the humble Russell's Viper kills humans by the hundreds. It seldom if ever figures in the "most dangerous snake" lists! The Cobras of Sri Lanka kill an average 5 people out of every 100 000 population per annum. Translated to the Australian scenario this would mean around 900 deaths per annum.

What these lists are giving us is the POTENTIALLY most dangerous snakes. A true list of the most FATAL TO MAN snakes would give us some very humble but widespread and moderately venomous snakes.

So what's the answer?

There is none - only an answer within defined parameters such as:

So who are the leading contenders?

This list is by no means complete.

Snake Symptoms Mortality Treatment
Asian pit vipers - from 2 to 5 ft. long, throughout Asia reactions and mortality vary, but most bites cause tissue damage and mortality is generally low.
Australian brown snakes - 4 to 7 ft. long very slow onset of cardiac or respiratory distress moderate mortality, but because death can be sudden and unexpected, it is the most dangerous of the Australian snakes antivenom.
Barba Amarilla or Fer-de-lance - up to 7 ft. long, from tropical Mexico to Brazil severe tissue damage common moderate mortality antivenom.
Black mamba - up to 14 ft. long, fast-moving, S and C Africa rapid onset of dizziness, difficulty breathing, erratic heart-beat mortality high, nears 100% without antivenom. antivenom.
Boomslang - under 6 ft. long, in African savannahs rapid onset of nausea and dizziness, often followed by slight recovery and then sudden death from internal hemorrhaging bites rare, mortality high antivenom.
Bushmaster - up to 12 ft. long, wet tropical forests of C and S America few bites occur, but mortality rate is high.
Common or Asian cobra - 4 to 8 ft. long, throughout S Asia considerable tissue damage, sometimes paralysis mortality probably not more than 10% antivenom.
Copperhead - less than 4 ft. long, from New England to Texas pain and swelling very seldom fatal antivenom seldom needed.
Coral snake - 2 to 5 ft. long, in Americas south of Canada bite may be painless, slow onset of paralysis, impaired breathing mortalities rare, but high without antivenom and mechanical respiration. antivenom.
Cottonmouth water moccasin - up to 5 ft. long, wetlands of southern U.S. from Virginia to Texas. mortality low, but tissue destruction can be extensive antivenom.
Death adder - less than 3 ft. long, Australia rapid onset of faintness, cardiac and respiratory distress at least 50% mortality without antivenom. antivenom
Desert horned viper - in dry areas of Africa and western Asia swelling and tissue damage low mortality antivenom.
European vipers - from 1 to 3 ft. long bleeding and tissue damage mortality low antivenoms.
Gaboon viper - over 6 ft. long, fat, 2-inch fangs, south of the Sahara massive tissue damage, internal bleeding few recorded bites. antivenom.
King cobra - up to 16 ft. long, throughout S Asia rapid swelling, dizziness, loss of consciousness, difficulty breathing, erratic heartbeat mortality varies sharply with amount of venom involved, most bites involve nonfatal amounts antivenom.
Kraits - up to 5 ft. long, in S Asia rapid onset of sleepiness, numbness up to 50% mortality even with antivenom. antivenom
Puff adder - up to 5 ft. long, fat, south of the Sahara and throughout the Middle East rapid large swelling, great pain, dizziness moderate mortality often from internal bleeding antivenom.
Rattlesnake - 2 to 6 ft. long, throughout W. Hemisphere. Rapid onset of severe pain, swelling mortality low, but amputation of affected digits is sometimes necessary Mojave rattler may produce temporary paralysis. antivenom.
Rinkhals, or spitting, cobra - 5 ft. and 7 ft. long, S Africa squirt venom through holes in front of fangs as a defense venom is severely irritating and can cause blindness. antivenom.
Russell's viper or tic-polonga - over 5 ft. long, throughout Asia internal bleeding moderate mortality rate, bite reports common antivenom.
Saw-scaled or carpet viper - up to 2 ft. long, in dry areas from India to Africa severe bleeding, fever high mortality, causes more human fatalities than any other snake antivenom.
Sea snakes - throughout Pacific, Indian oceans except NE Pacific almost painless bite, variety of muscle pain, paralysis mortality rate low, many bites are not envenomed some antivenoms.
Sharp-nosed pit viper or One Hundred Pace Snake - up to 5 ft. long, in S Vietnam and Taiwan, China the most toxic of Asian pit vipers, very rapid onset of swelling and tissue damage, internal bleeding moderate mortality antivenom.
Taipan - up to 11 ft. long, in Australia and New Guinea rapid paralysis with severe breathing difficulty mortality nears 100% without antivenom. antivenom.
Tiger snake - 2 to 6 ft. long, S Australia pain, numbness, mental disturbances with rapid onset of paralysis may be the most deadly of all land snakes though antivenom is quite effective. antivenom.
Yellow or Cape cobra - 7 ft. long, in southern Africa most toxic venom of any cobra, rapid onset of swelling, breathing and cardiac difficulties mortality high without treatment antivenom.
Note: Not all bites by venomous snakes are actually envenomed.
All animal bites, however, possibly carry tetanus, and anyone suffering a snake bite should seek medical attention.
Antivenoms do not cure they are only an aid in the treatment of bites.
Mortality rates above are for envenomed bites

Back to the Index Page.

Copyright: Séan Thomas & Eugene Griessel - Dec 1999.