The World’s 4 Deadliest Snakes: Why the “Big 4” Lead to 50,000+ Deaths Per Year

Deadliest Snakes - Indian Cobra
© Dr. Meet Poddar/

Written by Kyle Glatz

Updated: January 14, 2024

Share on:


Aside from mosquitos and humans, snakes are the deadliest animals on the planet, killing the third most people every year. On average, about 5.4 million people are bitten by venomous snakes, and half of these bites result in envenomation. Between 80,000 and 140,000 people die as a result of these bites and many more are left seriously injured. Upwards of 50,000 of these deaths happen on the Indian subcontinent alone, and of those bites, the so-called Big 4 are responsible for 75% of all bites and perhaps a greater number of fatal bites.

We’re going to take some time to get to know these deadly snakes. We’ll show you which of them is the worst of the worst and what makes them so dangerous.

What Are the Big 4 Snakes?

10 Most Venomous Animals - The Roman's Saw scaled Viper is the most dangerous snake in Africa and Asia

The Roman’s Saw scaled Viper is the most dangerous snake in Africa and Asia

©Luis Montero de Espinosa/

Russell’s ViperCommon KraitIndian CobraIndian Saw-Scaled Viper
Percent of all Medically Significant Snakebites43%18%12%1.7%
Mortality Rate2.6%6.4%6.5%-20%5%-20%

The “Big 4” snakes are currently Russell’s viper, common krait, Indian cobra, and Indian saw-scaled viper. Russell’s vipers are considered the deadliest because they bite the most people. About 43% of all medically significant snakebites in India came from this snake. Don’t let its low mortality rate make you believe they aren’t dangerous. That number, and all the others, account for cases where the individual receives antivenom treatments.

Common kraits are very deadly and account for a high number of snakebites. It’s believed that they kill about 10,000 people per year in India. The Indian cobra needs further studies to derive its true mortality rate, but it’s high even with treatment at 6.4%.

Lastly, the Indian saw-scaled viper bites the fewest people of all the Big 4, but it has very deadly venom and it is found in India and other places around the world. In fact, it might be the snake responsible for the greatest number of deaths annually in the entire world.

Which of the Big 4 Are Most Dangerous?

Most Venomous Snakes - Russell's Viper

Russell’s Viper is one of the deadliest

snakes in the world


Determining which of the Big 4 is most dangerous requires a fine understanding of what makes a snake dangerous. In this case, we know the snake that bites the most and kills the most people in India by sheer numbers is Russell’s viper, but it’s worth looking at other measures as well.

Russell’s Viper

Deadliest Snakes - Russell's Viper

Rusell’s vipers have a mortality rate of around 2.6% in India

©jaroslava V/

The Russell’s viper is the most dangerous of the Big 4 because it inflicts the most medically significant bites and has a high fatality rate. Since it’s responsible for 43% of the bites in India, this snake is very dangerous on that fact alone.

However, we must also consider that the snake is highly defensive and will bite without much provocation, a major difference from other snakes. Not only does this snake bite without a lot of warning, but the bite is also terribly painful because of the powerful venom.

Russell’s viper causes anywhere between 15,000 and 25,000 deaths in India each year by itself.  

Common Krait

Deadliest Snakes - Common Krait

Common krait bites can have up to an 80% fatality rate if not treated.

©Arabindu Sardar/

The common krait doesn’t kill as many people as Russell’s viper, but it might be more dangerous overall. This snake is known for having a mortality rate between 70% and 80% if the individual is untreated.

Their unique venom is a powerful neurotoxin that causes paralysis in the victim. Unfortunately, once this paralysis sets in, there is no means to reverse it. Despite having fewer than half the number of bite victims as Russell’s viper, it still kills about 10,000 people per year throughout India.

Indian Cobra


Indian cobra bites kill about 15,000 people annually.

©Chandan Singh from India, CC BY 2.0 – Original / License

The Indian cobra is the snake many people associate with deadly snakes in India. However, this snake is only responsible for about 12% of all the bites in the nation. Despite having moderately powerful venom, the Indian cobra manages to kill about 15,000 people across several countries, including India, every year.

Indian Saw-Scaled Viper

Deadliest Snakes - Indian Saw Scaled Viper

Saw scaled vipers may lead to the most fatalities of any snake when looking at worldwide totals.


The Indian saw-scaled viper is a very dangerous snake because it is very small, envenomates over 75% of all its bite victims, and has a high level of aggression. To make matters worse, it’s very quick, so it can bite people before they know what’s happening.

Although it’s not responsible for as many bites in India as it is elsewhere, it still kills about 4,000-5,000 people annually in India.  

The Big 4 snakes are highly dangerous for many reasons. Still, Russell’s viper is most dangerous in that it kills the greatest number of people. These others have aggressive demeanors, horribly toxic venom, and the habit of living in areas that are highly populated with human beings.

The Hump Nose Viper: A Newcomer in the Big 4?

Deadliest Animals - Hump Nosed Viper

The hump nose viper could be a future member of the Big 4.


A new study that was completed in 2020 yielded some very interesting data about snake bites in India. For example, a highly venomous snake called the hump nose viper delivered more bites than the Indian saw-scaled viper. Roughly 4% of all medically significant snakebites came from the former and 1.7% of bites came from the latter.

That seems to indicate that the hump nose viper could overtake the saw-scaled viper as one of the Big 4, at least in India.

What Makes The Big 4 So Deadly?

Deadliest Snakes - Snake in India

The Big 4 happen to coexist with about 20% of the world’s population of humans

©Nila Newsom/

We’ve already discussed the snakes’ venom and why that makes their bites so deadly. However, the number of people killed in the Indian subcontinent every year is simply astounding relative to the rest of the planet. Thus, we need to consider other factors that cause fatalities in this area. They include:

  1. The high population of people in this part of the world puts far more individuals in contact with snakes than usual.
  2. The snakes in this area are especially deadly species.
  3. Many bites occur in rural areas where there is no immediate medical attention available.
  4. Many individuals work in agriculture which puts them in danger of being bitten.
  5. Some clinics are too poor to stock enough antivenom for difficult cases or may not store it properly.

These factors complicate an already difficult matter. Every year, tens of thousands of people die in the Indian subcontinent from snakebites, and many more are left disabled by amputations, nerve damage, and lingering pain. Currently, the World Health Organization is undertaking studies on how to reduce deaths and injuries.

Let’ s take one last look at these four deadly snakes:

Discover the "Monster" Snake 5X Bigger than an Anaconda

Every day A-Z Animals sends out some of the most incredible facts in the world from our free newsletter. Want to discover the 10 most beautiful snakes in the world, a "snake island" where you're never more than 3 feet from danger, or a "monster" snake 5X larger than an anaconda? Then sign up right now and you'll start receiving our daily newsletter absolutely free.

Share this post on:
About the Author

Kyle Glatz is a writer at A-Z-Animals where his primary focus is on geography and mammals. Kyle has been writing for researching and writing about animals and numerous other topics for 10 years, and he holds a Bachelor's Degree in English and Education from Rowan University. A resident of New Jersey, Kyle enjoys reading, writing, and playing video games.

Thank you for reading! Have some feedback for us? Contact the AZ Animals editorial team.