Head to head
Cobra vs Viper
Cobras and vipers are the snakes most people picture when they think of venom, and they represent two different evolutionary answers to the same problem. The differences run through the fangs, the venom, the hunting style, and even the way each snake behaves when it is cornered.
| Cobra | Viper | |
|---|---|---|
| Family | Elapidae (Naja and relatives) | Viperidae |
| Fangs | Short, fixed, at the front of the jaw | Long, hinged, fold flat when closed |
| Venom type | Mainly neurotoxic, blocks nerve signals | Mainly tissue-destroying and anti-clotting |
| Warning display | Rears up and spreads a hood | Coils, hisses, some rattle or puff |
| Head shape | Fairly narrow, rounded | Usually broad and triangular |
| Hunting style | Active forager, hunts other snakes and rodents | Mostly sit-and-wait ambush |
| Heat sensing | No | Yes in the pit vipers |
| Serious bite kills by | Paralysing the breathing muscles | Bleeding, shock, and tissue death |
Cobra vs Viper: common questions
Which is more dangerous, a cobra or a viper?
It depends on the species and on what you mean by dangerous. Cobra venom acts faster on the whole body, and a large king cobra or a spitting cobra delivers a big dose, but cobras give a clear warning and many bites are defensive and partly dry. Vipers such as the saw-scaled viper and Russell's viper are small, superbly camouflaged, quick to bite with little warning, and extremely common in farmland, so they kill more people overall. A viper bite is also more likely to leave permanent damage to the limb even when the person survives. Both are treatable with the right antivenom given early.
How can you tell a cobra from a viper?
The clearest cues are the head and the body. A viper typically has a short, thick body and a broad, distinctly triangular head much wider than the neck, often with a blunt snout and vertical pupils. A cobra has a more slender, evenly tapered body and a narrower head that is not sharply set off from the neck, and when alarmed it lifts the front of its body and spreads a hood, something no viper does. Vipers tend to stay put and rely on camouflage, while a disturbed cobra rears and may advance. Never rely on these cues to handle a snake, since exceptions exist and mistakes are costly.
Why do cobras and vipers have such different venom?
Their venoms are tuned to how each snake hunts. A viper strikes from ambush, injects a big load of tissue-digesting venom, then releases the prey and tracks it by scent as the venom works and begins digesting it from the inside, which suits an animal that eats infrequently and cannot afford a struggle at close quarters. A cobra is a more active hunter that often holds onto prey, including other snakes, so fast-acting neurotoxins that shut the prey down quickly are more useful. Neither pattern is absolute, since some cobras have tissue-damaging components and some vipers have neurotoxins, but the broad split reflects the two hunting strategies.