When most people think of the deadliest animal in the world, their minds immediately turn to ferocious predators like sharks, lions, snakes, or crocodiles.
These creatures certainly inspire fear, but the reality is far more surprising.
The animal that kills the most humans each year isn’t massive or visibly dangerous. In fact, it’s small, nearly silent, and often goes unnoticed.
Here’s a breakdown of the world’s most dangerous animals and the number of human deaths they cause annually. Some of the culprits might shock you.)
9 animals that kill the most humans
1. Mosquito – 725,000 deaths per year)
The mosquito is, without a doubt, the deadliest animal to humans. Despite its tiny size, it is responsible for around 725,000 deaths every year. Mosquitoes are vectors for some of the most dangerous diseases on Earth, including malaria, dengue fever, Zika virus, yellow fever, and chikungunya.
Malaria alone causes hundreds of thousands of deaths annually, particularly in sub-Saharan Africa. The danger doesn’t come from the mosquito bite itself, but from the parasites and viruses they inject into the bloodstream. These diseases disproportionately affect children, pregnant women, and people in low-income regions with limited access to healthcare.
2. Freshwater snails – 200,000 deaths per year
It might be hard to believe, but freshwater snails are responsible for approximately 200,000 deaths each year. They carry parasitic flatworms that cause schistosomiasis, a disease that damages internal organs and impairs growth and development in children. The disease is transmitted through contact with contaminated freshwater, making it especially prevalent in communities that rely on rivers and lakes for bathing, washing, or drinking.
3. Saw-scaled viper – 138,000 deaths per year)
The venomous saw-scaled viper holds the record as the world’s most deadly snake in terms of mortality. Snakes overall are high up on the list of deadly creatures, as snake bites are responsible for as many as 138,000 deaths annually.
The saw-scaled viper is a particularly aggressive species, making it more deadly. Its aggressive nature, paired with its potent venom and presence in highly populated areas, makes the saw-scaled viper a snake to fear.
4. Assassin ugs – 10,000 deaths per year)
Despite the dramatic name, assassin bugs don’t kill through biting alone. These bugs transmit Chagas disease, a parasitic infection common in Latin America that kills roughly 10,000 people per year. Chagas disease often begins with mild or no symptoms, making it difficult to diagnose early. Over time, however, it can cause severe damage to the heart and digestive system, leading to sudden death if left untreated.
5. Scorpions – 2,600 deaths per year)
Scorpions produce venom for the same reason that many species do, not to kill humans, but to subdue or kill their prey. However, the venom of 25 species of scorpion can be deadly to humans if you are unlucky enough to get in one’s way.
Stings often happen when scorpions are accidentally stepped on with bare feet or when they are hiding in people’s shoes. They use it as a defence mechanism against getting crushed, rather than as an attack. Around 2,600 deaths a year are caused by scorpion stings. The most lethal in the world is considered to be the Indian red scorpion (Hottentotta tamulus).
6. Ascaris roundworms – 2,500 deaths per year
Ascaris roundworms are transmitted when a person accidentally ingests their eggs, which is unfortunately usually when food or drink is contaminated by human faeces. The worms take residence in the small intestine and use the human body to stay alive, feed and reproduce. The resulting disease is called Ascariasis, is characterised by fever, abdominal pain and swelling, and shortness of breath, and kills around 2,500 people every year.
7. Saltwater Crocodile – 1,000 deaths per year
Crocodiles are the most dangerous of the large predators, responsible for about 1,000 deaths each year. They tend to attack humans who venture too close to riverbanks or shallow waters, particularly in sub-Saharan Africa and Southeast Asia.
Unlike most animals on this list, crocodiles don’t kill through disease or poison like the other animals on the list; their method is brutally physical. They strike swiftly, dragging victims underwater before anyone even notices what’s happened. When pursuing prey through the water, they can also reach speeds of 18mph. All this together means that if a saltwater crocodile has chosen you as its prey, survival is unlikely.
8. Elephants – 500 deaths per year)
Despite their calm and majestic appearance, elephants cause around 500 human deaths each year, particularly in India and parts of Africa. These incidents often occur when wild elephants raid farms, leading to dangerous encounters with villagers trying to protect their crops. In some cases, stressed or provoked elephants can trample or gore individuals with lethal force.
9. Hippopotamus – 500 deaths per year)
Causing an estimated 500 deaths annually (as compared to only 22 for lions), hippos are deadly land mammals. This is because they are very aggressive and territorial, and have a habit of charging at boats and capsizing them. The people on board then either drown or are killed by the animals themselves. Weighing an average of 1,500 kg (males), with large, sharp teeth, it’s certainly an animal you wouldn’t want to face up against.
