The World's Deadliest Animals Might Surprise You

The deadliest animals can look more innocent than you think.
••• Photography by Zack Podratz/Moment/GettyImages

Did you see Jaws at a formative age and now can’t think about the ocean without being afraid of a toothy bite? Or caught a few attack scenes from Hitchcock’s The Birds and now harbor a kinda unhealthy fear of those creepy flying things? Can’t even think about spiders without getting a little chill in your spine?

We’re not saying there’s nothing to be scared of when it comes to sharks, spiders and birds. But for being such common fears, they actually rank pretty low on the list of animals that kill humans.

Some killer animals don’t have the menacing jaws of sharks, creepiness of spiders or the inherent ... strangeness of tiny dinosaur relatives. But they wield power in different ways, often with deadly consequences. Curious which animals you’re going to start being afraid of? Keep on reading.

The Obvious Ones

There are deadly animals that you’ve been warned about your whole life, or loom large enough that you’d never choose to be left alone in a room with them. Lions, for instance – the kings of the jungle have earned a bad reputation thanks to their threatening growl and incidents like the Man-Eaters of Tsavo, a duo of lions that killed as many as 135 people building a Kenyan railroad more than 100 years ago. The animals still kill about 250 people each year, but they typically don’t go after humans without instigation, mostly attacking the poachers or tourists who get up in their business.

Another unsurprising killer is the crocodile, claiming more than 1,000 human lives each year. It’s not a pretty way to go – these predators are known for their ability to ambush victims and then tear them apart or drown them.

And we can’t forget about snakes. People around the world are spooked by these slithering reptiles, but with good reason. Hundreds of varieties of snakes are estimated to kill about 60,000 people per year, typically through venom. The poison doesn’t always lead to instant death – if a bite victim is too far away from medical treatment, they can die slowly as the venom wreaks havoc in their body. Other deadly stings come from jellyfish and bees, hornets and wasps, which kill an estimated 50 and 65 people each year, respectively.

There’s another killer animal that’s obvious to some, but doesn’t come to mind for others: humans. We’re mammals, after all, and we go around killing each other through different forms of warfare and violence.

The Not-So-Obvious

The least obvious but deadliest animals tend to be tiny. A lot of them are worms. Not the earthworms helping to nurture your backyard garden, but hungry, parasitic ones that get into a victim’s digestive system, eat everything they can find, suck all the nutrients out of an otherwise healthy person and eventually get so big that they can shut down organs.

Treatment works, but these often hit in underserved areas where treatment can be slow, lacking or even nonexistent. Tapeworms, roundworms and other parasite-causing worms can cause more than 60,000 deaths per year, and lead to serious illness in hundreds of thousands more people. And it’s not just worms. Tsetse flies, freshwater snails, kissing bugs and sandflies can also cause parasites that kill tens of thousands more each year.

There’s one more tiny killer to rule them all: the mosquito, carrier of diseases like malaria, yellow fever, Zika virus, West Nile virus and dengue fever. The World Health Organization estimates the bugs kill as many as 725,000 people per year, and incapacitate millions more. Health and policy officials have undergone massive efforts to curb populations and get better treatment to people, but it’s still a rampant killer on the loose.