Which is More Venomous? Rattlesnake vs. King Cobra

Written by Brandi Allred
Updated: April 15, 2023
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There are many venomous snakes in the world, but few are more feared than the rattlesnake or the king cobra. But, of the two, which is more venomous? A venomous snake is defined as one that bears venom. That venom is almost always used to incapacitate and kill prey, but it can also be used for self-defense. Unfortunately, human-snake interactions often result in envenomation. Untreated snakebites can quickly lead to serious complications, loss of limbs, or even death for humans.

Here, we’ll compare the venom of the eastern diamondback rattlesnake (one of the deadliest rattlesnakes in the world) with the venom of the king cobra. We’ll go over just how potent each snake’s venom is and how many people are bitten (and killed) every year by these deadly species. Finally, we’ll answer the question: which is more venomous, the rattlesnake or the king cobra?

Rattlesnake (Crotalus adamanteus)

Large eastern diamondback rattlesnake

Eastern diamondback rattlesnakes are not in danger of extinction.

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©Chase D’animulls/Shutterstock.com

The eastern diamondback rattlesnake is the largest of all rattlesnakes. They can grow to over six feet long and weigh more than 10 pounds. Eastern diamondbacks live only in the southeastern United States, where they hunt mainly rodents. They’re known for their unwillingness to back down and will readily bite and envenomate humans who come too close.

Rattlesnake Venom

Eastern diamondback rattlesnakes are pit vipers. They have hemotoxic venom that acts on the nervous and circulatory systems. In rodents, this venom results in rapid organ failure and death. Let’s take a look at the statistics surrounding rattlesnake venom to determine which is more venomous, the rattlesnake or the king cobra.

Annual Deaths from Rattlesnake Bites

Together, the eastern diamondback rattlesnake and the western diamondback rattlesnake cause 95% of all snakebite deaths in the United States. On average, about five people per year die from snake bites in the United States. Nearly 2,000 people sustain rattlesnake bites every year, but thanks to the wide availability of antivenom, very few victims die.

Venom Dosage

When rattlesnakes bite, they don’t always inject venom. Bites without venom are known as ‘dry’ bites; dry bites occur 20-25% of the time. On average, eastern diamondbacks inject 400-450 mg of venom per bite, though it only takes about 150 mg to kill a human.

Effects of Rattlesnake Venom

Locally, rattlesnake bites cause two puncture wounds that rapidly swell. The flesh around the wound necrotizes (dies) as a result of the venom’s pre-digestion enzymes. Throughout the body, rattlesnake venom can cause organ failure, systemic infection, hypotension, and death. Though, few people die from rattlesnake bites or develop severe complications. 

The risk of complication and death is directly proportional to the amount of venom injected, the injection site, and the amount of time between injection and treatment with antivenom. 

King Cobra (Ophiophagus hannah)

King cobra

King cobras are often killed or captured as part of the global trade in illegal wildlife.

©Eric Isselee/Shutterstock.com

The longest venomous snakes on earth are the King cobras. They’re famous for their long fangs (though not as long as a rattlesnake) and wide hoods. The hoods are actually made of flattened ribs, which the cobra displays when threatened. King cobras live in the south and Southeast Asia and can grow to nearly 20 feet long. Their bodies are dark brown to black, with white stripes and pale bellies. Baby king cobras have distinct yellow stripes along their bodies.

King Cobra Venom

When it comes to determining which is more venomous, rattlesnake or king cobra, it’s important to know the differences between their venoms. King cobras have neurotoxic venom that also contains cytotoxins. Like the rattlesnake, the king cobras store their venom in venom glands near the eyes. So, even a severed king cobra head can still bite and envenomate. Many of those bitten are people attempting to use the snakes for ‘snake charming’.

Annual Deaths from King Cobra Bites

King cobra bites are extremely rare, and almost always occur when people attempt to handle these impressive snakes. Most bites happen in the king cobra’s native countries of Malaysia, China, and India. There is no data on just how many people king cobras bite every year. But, due to the shy and cryptic nature of these huge snakes, contact with humans is rare, and so are their bites. 

Venom Dosage

King cobras deliver 400-600 mg of venom per bite, which is enough to kill humans several times over. However, not all bites result in envenomation, which means that some bites actually inject no venom. King cobras can bite multiple times in quick succession, injecting more venom with every strike.

Effects of King Cobra Venom

Like rattlesnake venom, king cobra venom causes local necrosis and tissue damage. Often, affected extremities have to be amputated. Across the body, a single venom-bearing bite from a king cobra can cause death in humans in as little as 30 minutes. This is because the king cobra’s venom affects both the nervous and cardiovascular systems. Envenomation can lead to shock, paralysis, organ failure, and death.

Rattlesnake vs King Cobra: Which is More Deadly?

Rattlesnake Fangs

With such potent venoms, you don’t want to risk a bite from either the eastern diamondback rattlesnake or the king cobra.


So, which is more venomous, the rattlesnake or the king cobra? 

Let’s start by saying that a bite from either snake is a big deal; both require hospital visits and doses of antivenom. Both snakes sometimes dry bite, injecting no venom. But, both snakes are also capable of biting and envenomating a victim multiple times. But, only one can have the deadliest venom.

King cobras are more venomous than rattlesnakes. Their venom is both more potent and comes in higher quantities. However, king cobra bites are rare, much rare than rattlesnake bites. So, pound for pound, the king cobra is more venomous than the rattlesnake, but the rattlesnake presents more of a threat to humans.

The photo featured at the top of this post is © iStock.com/DaveGartland

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About the Author

Brandi is a professional writer by day and a fiction writer by night. Her nonfiction work focuses on animals, nature, and conservation. She holds degrees in English and Anthropology, and spends her free time writing horror, scifi, and fantasy stories.

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