That’s not a trick question. Truth is, when you factor in all the ways human beings are capable of killing themselves and each other, it is likely that more people are killed by humans, than any other creature on the planet.
But other than human beings, there is one creature that kills more humans than any other.
There is, however, one creature that kills more humans than any other.
You might think it would be snakes, lions, elephants, the hippopotamus, or sharks. You’d be right that any one of these creatures kill quite a few humans each year.
But none of these animals, bugs, or reptiles kill more than the itsy-bitsy mosquito. Mosquitoes transmit life-threatening diseases that kill 725,000-1,000,000 people every year.
The word mosquito comes from the Spanish meaning “little fly.” Their bodies are slender and segmented, with one pair of wings, a pair of halteres (two small club-shaped organs that help with body stabilization during flight), three pairs of long, hair-thin legs, and elongated mouthparts.
There are four stages to the mosquito’s life cycle: egg, larva, pupa, and adult. The female lays her eggs by flying over the surface of the water, bobbing up and down to drop eggs as she goes. A female mosquito can lay 100-200 eggs during the course of the adult phase of her life cycle.
Adult mosquitoes typically mate within days after emerging from the pupal stage. It is a rather impersonal process, as the males simply swarm together around dusk and the females fly into the swarm to mate.
When the eggs hatch, the larvae eat the algae and other organic material in the water. During this stage, the larvae can become a meal for freshwater animals, such as dragonflies, fish, and ducks.
The female mosquito is equipped with a proboscis—a tube-like mouthpart that can pierce the skin of its host and feed on their blood. The protein and iron they get from the blood helps in the production of eggs and thereby, the perpetuation of the species.
Male mosquitoes live for about five to seven days. Females live about a month in nature. Their lifespan is determined by temperature, humidity, and their ability to find a continual supply of hosts without becoming a meal themselves.
Mosquitoes don’t live or function well in temperatures below 50° F and are most active in temperatures between 59°-77° F. There are thousands of species of mosquitoes all around the world feeding on mammals (including humans), birds, reptiles, amphibians, and even fish.
Mosquitoes are known as vectors of parasitic diseases. That means they are a living agent that carries and transmits an infectious pathogen to other living organisms. While biting an infected host, they ingest pathogens and then through their saliva, transfer that pathogen to the next host. Only the females of certain species of mosquitoes spread these pathogens. In the United States, those species are: Anopheles, Aedes, and Culex. According to the World Health Organization, some of those diseases include: chikungunya, dengue, lymphatic filariasis, Rift Valley fever, Yellow fever, Zika, malaria, Japanese encephalitis and West Nile fever.
The worst disease carried by mosquitoes—simply because it kills so many people—is malaria, caused by a single-cell parasite called Plasmodium. It kills “more than 600,000 people every year; [with] another 200 million incapacitated for days at a time. It threatens half the world’s population, and causes billions of dollars in lost productivity annually.” This little parasite infects the mosquito, and once it reaches the mosquito’s midgut, the parasites multiply and migrate back to the salivary glands.
Many of the diseases spread by mosquitoes are endemic [restricted] to particular areas of the world and not often found in the United States and Europe, except perhaps in the case of the hapless traveler. Malaria, for example, is found mainly in areas with climatic factors like temperature, humidity, and rainfall—northern South America, Saudi Arabia, most of Africa, and Asia. African countries make up about 96% of all malaria deaths. In high altitude areas, colder seasons, and deserts, malaria does not occur or is less intense and more seasonal.
But why doesn’t the mosquito get sick from the infectious pathogen/parasite she picks up? Awanish Mishra at the National Institute of Pharmaceutical Education and Research Guwahati believes that it might be because the pathogen/parasite itself never comes into direct contact with the mosquitoe’s circulatory system. And El-Desouky Ammar at the University of Florida, IFAS & ARS-USDA suggests that the mosquito and the pathogen/parasite have a symbiotic relationship that is beneficial to both.
To reduce the chances of becoming an early-evening snack for a group of lady mosquitoes this summer, follow these, and other, common sense guidelines:
• Monitor and disrupt standing water in gutters, uneven concrete, potted plants or spare tires on a weekly basis
Discard waste in sealed plastic bags and ensure trash is collected regularly
Fit water storage containers with tight lids and use fine-mesh coverings on storage vessels
Wear light-colored, long-sleeve clothes, use insect repellent and sleep under a bed net
Fit windows and doors with screens
Use insecticide sprays or vaporizers in and around houses
Sources: worldatlas.com/animals/10-animals-that-kill-the-most-humans; smithsonianmag.com/smart-news/mosquitoes-kill-more-humans-human-murderers-do; cdc.gov/malaria/about/distribution; Wikipedia.org/wiki/Mosquito; researchgate.net/post/Why_vector_mosquitoes_dont_get_affected_by_the_viruses_plasmodium_they_transmit; usatoday.com/story/news/health/2023/02/02/what-animal-kills-most-humans
| Animal | people killed | note |
| Snake | 50,000 | |
| Dog | 25,000 | mainly from the transmission of rabies |
| Assassin Bug | 10,000 | includes the tsetse fly, a primary carrier of malaria |
| Freshwater Snail | 10,000 | parasitic worm that carries the disease schistosomiasis |
| Scorpion | 2,600 | |
| Roundworm &Tapeworm | 2,000-2,500 | |
| Crocodile | 1,000 | |
| Hippopotamus | 500 | |
| Elephant | 100 | |
| Lion | 100 | |
| Shark | 10 |