Every year somewhere between 20,000 and 125,000 people die from snake bites. This makes them by far the most dangerous group of vertebrates on Earth.
Like all lists on Planet Deadly there is some balancing here of what criteria actually define the world’s deadliest snakes. Other lists on various websites should probably be more accurately titled as the “World’s most venomous snakes” and this was partially covered in our article on the most venomous animals.
Whilst the strength of the snake’s venom is obviously an important factor in how dangerous it is, there are other equally important things to consider. Let us take the most venomous of all the snakes, the inland tiapan. Now, this doesn’t even feature here, in fact it didn’t even make it on to our list of Australia’s most dangerous animals. Why? Well, firstly no one ever seems to be killed by these snakes. They live in remote areas, are highly timid and really don’t go looking for trouble.
On the other hand a snake like the Indian cobra has venom over 30 times less potent than the inland taipan yet kills thousands of people every year. In my opinion this makes the cobra a far more deadly snake that the taipan, and that is why you will find it on this list.
And in case you thought it was only live snakes that were dangerous, think again – some snakes retain the reflex to bite even after death. These can actually be more dangerous as they lose the ability to regulate the venom they inject resulting in higher levels of envenomation.
10. Death Adder
On name alone the death adder qualifies for a place on our list. However, the name actually started out as “deaf adders” as in the old days it was believed they couldn’t hear. The reason for this misconception was that unlike other snakes, which tend to slither away when a human approaches, the death adder doesn’t. This is because they are ambush hunters which lay in wait for their prey and so are less inclined to move.
Regardless of where the name comes from though, these are a very dangerous snake indeed. Their venom is some of the most powerful on earth and contains neurotoxins capable of causing paralysis of the respiratory system and death. As well as being armed with such lethal venom the death adder is just about the fastest striking snake you’ll find anywhere.
The death adder is found throughout much of Australia where it is considered less dangerous than the brown snakes. They are also found in Papua New Guinea and western Indonesia where they do unfortunately live up to their name and cause a significant number of deaths every year.
9. Coastal Taipan
It may seem strange that the most venomous snake on Earth (the inland taipan) did not make it onto the list whereas its less venomous cousin, the coastal taipan, did. Whilst the coastal taipan only (!) has the third most toxic venom of any land snake it is still phenomenally dangerous. Yes, admittedly it does only deliver sufficient venom to kill over 200,000 mice with a single bite – the inland taipan could theoretically kill over a million. But there are two important factors that I feel make the coastal taipan more dangerous; firstly it occurs in less remote regions than the rarely seen inland taipan and secondly the coastal taipan has a reputation as being somewhat aggressive.
When a coastal taipan feels the need to defend itself it goes into full attack mode. There is no messing around with ‘dry bites’, in over 80% of cases a large dose of venom is delivered, often in repeated strikes. Each of these rapid succession of bites is capable of injecting a similar amount of venom. With the longest fangs of any of Australia’s venomous snakes the taipan can inject its powerful neurotoxin deep into the victim’s tissues. Another of the taipan’s other reputed deadly traits is to actually chase people when on the attack, and it can move at a fair pace.
What really seals the taipans place on this list though is how lethal it is. Whilst other snakes may seem as dangerous on paper, none have the near 100% kill rate of the taipan’s bite if untreated. It has only been since the introduction of an antivenom in 1956 that a bite from a coastal taipan has been effectively survivable.
Even so, the venom is fast acting; in some cases the victim has been dead within half an hour. It works by affecting the nervous system leading to complete paralysis, including the lungs (which is pretty fatal). The venom also prevents the blood from clotting which causes internal bleeding and there is also a component which breaks down muscle tissue.
If this were “Top Trumps” then the coastal taipan would probably be the star card and head up our list of deadliest snakes. However, the statistics just don’t back it up. There are snakes out there that kill tens of thousands of people every year yet the taipan rarely kills anyone in Australia and only a handful in Papua New Guinea. This is testament to the life-saving antivenom serum developed by the Commonwealth Serum Laboratories in the 1950s. Without that, this list would probably look a little different.
8. Common Lancehead
The lanceheads are a family of pit-vipers (Bothrops) found throughout Central and South America. Together they are responsible for the vast majority of snakebite deaths in the region. Often living in populated areas these snakes are fast and described as excitable and unpredictable when encountered.
Worthy of particular mention amongst this group are the common lancehead (B. atrox), the terciopelo (B. asper) and the jararaca (B. jararaca). All are large snakes measuring around the 2 metre (6.5ft) mark and have powerful hemotoxic venom.
Unlike the previous two snakes which possess a neurotoxic venom, the lancehead’s venom is hemotoxic. Obviously, no one in their right mind wants to be bitten by any of the snakes on this list, but given the choice I’d go for a snake with neurotoxic venom any time. Hematoxins work by destroying blood cells and breaking down the body’s tissues and organs. As you might imagine this is both extremely painful and can result in irreversible damage. Bites from such snakes frequently result in the need to amputate limbs, even after prompt treatment.
The bite from a lancehead will cause local swelling and pain often followed by blistering and bruising. Systemic symptoms usually involve hemorrhaging internally and from the gums, eyes etc. Whilst this may lead to fatal shock, death may also result from kidney failure.
7. Puff Adder
The puff adder makes up for a lack of length with an abundance of girth. These heavily built snakes are powerful and equipped with particularly long fangs which make them formidable hunters. Despite being so slow and lethargic as to be described as ‘lazy’, the puff adder actually has one of the fastest strikes of any snake. It has been known for a puff adder to kill its rodent prey just from the sheer force of its strike and its large fangs. That said, it carries enough venom to kill several humans.
The name puff adder comes from the snake’s warning behaviour in which it will inflate itself to look bigger and release an intimidating hiss. You are well advised to heed this warning as the puff adder is statistically Africa’s most dangerous snake causing more fatalities than any other reptile on the continent.
To a large extent the puff adder’s grim record is due to its habit of basking on footpaths, soaking up the morning and late afternoon sun. This puts into contact with humans and this is compounded by the fact that these snakes are reluctant to slither away when they detect approaching footprints. Instead puff adders rely on their effective camouflage to remain undetected. Unfortunately this tactic can put the snake into a situation where it feels it needs to defend itself.
If you are bitten by a puff adder you will know about it; their cytotoxic venom is one of the most powerful of all the vipers and if not properly treated can cause death in over half of envenomations. The bite itself causes considerable pain but this is only the start of some very nasty symptoms. As well as swelling and internal bleeding the puff adder’s venom is known to cause tissue necrosis with severe cases causing damage right down to the bone. In the absence of effective medical treatment complications such as gangrene or not unusual and bite victims often require limbs to be amputated.
6. Indian Cobra
The infamous cobra is our first member of the “big four” – a group of snakes which cause the most human fatalities in India (and therefore the world). Whilst it is often only described as moderately venomous it makes up for this in sheer effort, delivering somewhere between 100,000 and 150,000 bites a year. Whilst the actual statistics for deaths caused by the Indian cobra are not available an estimate can be made from the mortality rate, which is given as anywhere between 6.5% and 30%. Whatever the correct figures are the fact is that many thousands of deaths are caused by this snake every year.
Whilst the Indian cobra’s venom might not quite match up to some of the heavyweights on this list it is still not to be underestimated. A cocktail of neurotoxins, cardiotoxins and hemotoxins the bite from a cobra can be extremely painful and rapidly fatal. The hemotoxins break down local tissue helping the venom spread whilst the neurotoxins cause paralysis. This in turn can result in respiratory failure, all of which may only take half an hour. Therefore, prompt treatment with antivenom is essential.
Apparently cobra venom is also occasionally used as a recreational drug. Yes, there are actually people out there willing to inject themselves with this to get a quick hit. Apparently the positive effects include; enhanced sensation, increased energy and “sense of well-being”. On the downside, side-effects include death.