The Seven Deadliest Reptiles

Which are the world’s seven deadliest reptiles? A simple enough question, you’d think, but ask 10 different reptile fans for their nominations and the chances of getting even two to agree are pretty small, never mind all of them! There’ll probably be two or three animals that appear on everyone’s list, but in the end it largely comes down to personal opinion – and just how do you define deadly anyway? Is it all about any given species’ potential to kill, or about the numbers of actual recorded fatalities?

However you make your choice, you can be sure that, sooner or later, someone’s going to disagree with you – but hey; that’s life! So with that firmly in mind, here are our suggestions for the seven deadliest reptiles. They’re in no particular order and you are, of course, entirely free to disagree.


“No animal is half as vile as Crocky–Wock, the crocodile” – or so wrote Roald Dahl and it’s an opinion that many people seemed to have shared over the years. It’s not hard to see why; the idea of being eaten alive is a pretty revolting one at the best of times, but when the threat comes in the shape of something that looks like it should have died out 60 million years ago, somehow it seems all the worse – if that’s possible.

There are recorded cases of many species of crocodilians attacking humans, even some kinds which are usually considered fairly docile, but most of these encounters tend to occur when the animal is surprised, trodden on accidentally or cornered and unable to escape. Two species, however, have a justifiable reputation as man-eaters and earn their places in the roll call of the world’s deadly seven:

  • Saltwater or Estuarine Crocodile (Crocodylus porosus) – with big males weighing more than a tonne and exceptionally reaching 6 metres in length, it is the largest living reptile.
  • Nile Crocodile (Crocodylus niloticus) – with a maximum size only half a metre or so shorter and 100kg lighter, this is another croc you certainly don’t want to mess with!


Scientific opinion has changed recently over the whole question of poisonous lizards. Until a few years ago, only two close relatives – the Gila Monster (Heloderma suspectum) and the Beaded Lizard (H. horridum) – were thought to be venomous, but now research suggests that many more lizards may possess some form of venom. Never-the-less, recorded fatalities from the Heloderms are rare and their ability to bite has been known about for centuries!

Although most lizards are too small to do much harm to a human, some of the bigger and more aggressive ones can pose a serious risk of injury – and one of these in particular, with its powerful body and toxic saliva, makes it onto the list:

  • Komodo Dragon (Varanus komodoensis) – growing to 3 metres and weighing 150kg, it’s a midget compared with the crocodiles, but it’s the largest lizard in the world – and the most deadly.


Which is the world’s most dangerous snake? It’s a question that pops up time and time again and hardy anyone ever agrees! If you take a view just on drop-for-drop venom potency, then the sea snakes come out way ahead of the rest – but human deaths are unbelievably rare since they are very docile, hardly ever bite and don’t often come across people. Apply the same thinking to land snakes, and most people would settle on the Inland Taipan (Oxyuranus microlepidotus) – otherwise known as the Fierce Snake, which probably gives a bit of a clue as to why!

All of that, however, still leaves the real question – which are the most deadly, and qualify for inclusion among this magnificent seven? Perhaps one way to decide is to look not at the power of their poison, but the body count. On that basis, here are the most consistent killers for their part the world and definitely four of the world’s most deadly reptiles:

  • Puff Adder (Bitis arietans) – in Africa
  • Brown Snake (Pseudonaja textilis) – in Australia
  • Fer-de-Lance (Bothrops asper) – in Central and South America
  • Western Diamondback Rattlesnake (Crotalus atrox) – in North America

So – do you agree with the selection, or are there other candidates that you think should have been included? To tell the truth, there almost certainly are, but go on, admit it. It’s made you think about your own top seven, now hasn’t it?

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