Which snake is the most venomous? And which is the swiftest? Despite their bad reputation, not all snakes are harmful and even the deadliest snakes tend to bite only in self-defence. However there are some you may want to avoid.

Burmese Python

Ray Mears on Adders


Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: Squamata
Superfamily: Varanoidea
Suborder: Serpentes


Snake venom is a complex mixture of proteins that once unleashed rapidly spreads through the victim's body with delivery via specialised fangs. Unlike regular teeth, the fangs of a venomous snake are hollow. This means they can inject their toxin with the efficiency of a hypodermic syringe. And they don't need much, the venom of a cobra could kill an elephant. Neurotoxic venom, which destroys the nervous system, is the variety that kills quickest.

Spitting cobras actually spray their venom with quick muscular contractions that can send their toxin up to three metres away. Worse still, they'll be aiming at your eyes when they do it.

Western diamondback rattlesnake coiled to strike

Western diamondback rattlesnake coiled to strike

Another snake to be wary of is a dead snake. Incredibly, a dead rattlesnake can still bite if you get too close. The snake's heat sensors remain active until rigor mortis is complete, a day or more later. Remarkably, placing a warm object, such as your hand, near the snake's mouth may still cause it to have a go!

Although cobras and mambas get all the notoriety, but the most venomous snake of all is the inland taipan of Australia. It could kill 100 people with a single bite, but thankfully it is quite placid and reserves its wrath for rats.


Constricting snakes are usually blessed with massively flexible jaws and muscular bodies. Pythons can and will crush and eat just about anything. A large meal, say, a human being, will sustain one of these snakes for a year or more.

Quick Facts

  • Some snakes, such as the king cobra, will eat other snakes.
  • Britain boasts three; the adder, grass snake and smooth snake.
  • Adders are the UK's only venomous snake, but its bite is very rarely fatal.
  • The swiftest snake on land is the black mamba, reaching 12 mph.