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

Written by Kyle Glatz
Published: March 16, 2022
Image Credit Dr. Meet Poddar/Shutterstock.com
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Think You Know Snakes?

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/Shutterstock.com

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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

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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/Shutterstock.com

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 aggressive 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/Shutterstock.com

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

Deadliest Snakes - Indian Cobra
Indian cobra bites kill about 15,000 people annually.

Dr. Meet Poddar/Shutterstock.com

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.

reptiles4all/Shutterstock.com

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.

ananth-tp/Shutterstock.com

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/Shutterstock.com

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.

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About the Author

I am a freelancer specializing in SEO content writing. I write in a variety of niches such as video games, animals, and managed service providers. I've been writing full-time since 2018, so I've been doing remote work before it was cool. When I'm not working, I can be found reading, trying to catch up on my tv show backlog, playing video games, and starting stories that I'll never finish.

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