Head to head
King Cobra vs Eastern Diamondback Rattlesnake
The king cobra of Asia and the eastern diamondback rattlesnake of North America are two of the most famous venomous snakes in the world, from opposite branches of the venomous-snake family tree — an elapid and a pit viper — with very different venoms and very different ways of warning you off.
| King Cobra | Eastern Diamondback Rattlesnake | |
|---|---|---|
| Family | Elapid (cobras, mambas, sea snakes) | Pit viper (rattlesnakes, copperheads) |
| Length | 3–4 m, up to 5.85 m — longest venomous snake | 1.1–1.8 m, up to 2.4 m — heaviest rattlesnake |
| Fangs | Short, fixed at the front of the mouth | Long, hollow, hinged; fold back when closed |
| Venom type | Mainly neurotoxic — shuts down breathing | Haemotoxic/cytotoxic — destroys tissue, disrupts clotting |
| Venom per bite | Very large volume; can kill an elephant | Large dose through long fangs; ~10–20% untreated fatality |
| Warning display | Rears up, spreads hood, growls (low hiss) | Coils, raises rattle, buzzes; stands its ground |
| Diet | Almost entirely other snakes | Rabbits, rats, squirrels, ground birds |
| Heat sensing | No — hunts by sight and smell | Yes — facial pits form an infrared image of prey |
| Conservation status | Vulnerable | Least Concern (declining in the US) |
Cobra vs Rattlesnake: common questions
Which is more venomous, a cobra or a rattlesnake?
It depends how you measure. The eastern diamondback’s venom is more toxic drop-for-drop than a king cobra’s, but the king cobra injects a far larger volume per bite, so the total dose delivered is greater. The venoms also act differently: the cobra’s attacks the nervous system and can stop breathing, while the rattlesnake’s destroys tissue and interferes with blood clotting.
Who would win, a king cobra or a rattlesnake?
The king cobra is the likely winner. It is several times longer, it specialises in eating other snakes and has partial immunity to snake venom, and its reach and speed let it deliver the first bite. The diamondback’s longer fangs and potent venom keep it dangerous, but it would be the underdog against a much larger, snake-hunting opponent.
What is the main difference between a cobra bite and a rattlesnake bite?
A cobra bite (elapid) tends to cause relatively little local swelling at first but progressive weakness, drooping eyelids, and difficulty breathing as the neurotoxin takes hold. A rattlesnake bite (pit viper) causes immediate intense pain, rapid swelling, bruising, and blistering around the wound, with bleeding problems and possible tissue loss. Both require prompt antivenom.