When you think of the world’s deadliest animals, you probably think of terrifying apex predators like bears and sharks. However, some of the most deadly animals on the planet are so small they’re barely noticeable. These terrifying creatures kill in a variety of ways, from full-on attacks to passing on deadly diseases, but they all kill many people every year. Even if you love the great outdoors, these deadly creatures may convince you never to leave your home again.

Mosquitoes

Almost everyone has been bitten by a mosquito at some point in their lives, so it’s easy to ignore the dangers of this tiny insect. However, mosquitoes are by far the deadliest animals on the planet. Their bites pass on some of the world’s most fatal diseases, including malaria, encephalitis and yellow fever. When you tally up all these deaths, mosquitoes kill an estimated 750,000 people every year.

Dogs

It’s hard for most people to think of cute, cuddly dogs as a danger, but man’s best friend is responsible for about 25,000 people each year. However, this isn’t because packs of aggressive dogs are mauling people left and right. Most are due to rabies, which stray dogs often carry in India, Thailand, Cambodia, and other countries. Many of these bites are fairly minor. Deaths due to injuries sustained in a dog attack are much rarer.

Snakes

From rattlesnakes in the western United States to cobras and vipers in Asia and Africa, the world is full of venomous snakes. Together, they kill around 50,000 people each year. Some, like the western diamondback rattlesnake in the United States, are reclusive and only bite a few people, many of whom do not die. However, others are more aggressive and live in highly populated areas. One of these is the saw-scaled viper, which can be found in parts of Asia, the Middle East, and Africa. Although around 90% of its bite victims survive, it still kills about 5,000 people annually.

Tsetse Fly

Located throughout much of sub-Saharan Africa, this unassuming-looking fly would just be a minor annoyance if not for a deadly disease spread through its bite. It spreads African sleeping sickness, a parasitic disease that causes neurological symptoms and is frequently fatal if left untreated. The tsetse fly was causing as many as 300,000 new infections a year during the height of some historic epidemics, although in recent years the number can be as low as around 2,000 due to eradication and control efforts.

Crocodiles

Crocodiles are one of the most fearsome predators in the world, killing about 1,000 people every year. Humans may not be their preferred prey, but they’re not afraid to attack if one swims by without realizing the danger. Since crocodiles hunt by hiding and then ambushing their prey, this can be hard to avoid. Their cousin, the alligator, is still dangerous to humans but tends to be less willing to hunt people actively.

Hippopotamus

These awkward-looking creatures may look like gentle giants, but appearances can be deceiving. Hippos are notoriously territorial and aggressive creatures, even going so far as to sink or tip over boats that pass too close. They attack both by biting and crushing people with their sharp teeth and strong jaws or simply holding their victims under the water until they drown. Hippos kill about 500 people a year.

Elephants

Elephants are known for their intelligence and emotional depth, and they often are able to coexist peacefully with humans. However, elephant attacks are increasing, leading to up to 500 human deaths each year. These attacks typically occur due to humans trying to chase elephants out of their territory or when elephants have been otherwise harassed and attacked by humans. Unprovoked attacks remain rare.

Box Jellyfish

You’re swimming along in the ocean, enjoying a beautiful day at the beach, when suddenly you feel a crippling pain. You may have inadvertently swum into the tentacles of a box jellyfish, a creature notorious for its incredibly painful stings. These translucent creatures drift slowly along in the water and are difficult to see and avoid, so many hapless swimmers are stung every year. Luckily, most do survive, although severe pain can linger for weeks. However, the venom is strong enough to kill, plus the paralyzing pain can lead to drowning. Over 100 people die from these stings every year.

Cone Snails

Cone snails don’t actually kill many people, but that’s mostly due to luck and humans knowing to leave them alone. These tropical snails have a beautiful and distinctive shell that is often collected for jewelry and other decorative uses, but only after its resident has vacated. When people do bother them, the snail may sting them with a sharp, harpoon-like appendage that injects one of the strongest venoms in the animal kingdom. This causes nearly immediate and complete paralysis and death, although at least it happens quickly. Most reported deaths happened within minutes of the initial sting.

Lions

These fearsome predators mostly leave people alone, but when they don’t, humans tend not to fare well. It’s difficult to find out exactly how many people die from lion attacks due to problems with reporting, but approximately 22 people are killed by them each year in Tanzania alone. Many of the attacks are due to human provocation, such as poachers attempting to hunt them. Some lions, such as the famous man-eating pair that terrorized railway workers in Tsavo in 1898, even seem to develop a preference for hunting humans.