The World’s Deadliest Animal: Mosquito

There is an annoying creature accompanying us on hot summer days. In addition to the itching of the bite site for days, it also poisons our night with its “buzz buzz” sound. It is such a creature that, according to a 2016 report by Business Insider, it is the deadliest animal in the world, causing an average of 750,000 deaths per year. Even we humans, the second most dangerous creature, are the killers of an average of 437,000 people. Yes, I’m sure we all thought of the same creature: mosquitoes.

So how do these tiny creatures find us? Why do they bite? Let’s find answers to these questions!

Space Age Sensors of Mosquitoes

Mosquitoes have been with us for more than 30 million years and have to feed like all other living things. It seems that they have mastered biting, gaining traits that will greatly improve themselves over these many years. Mosquitoes work like high-tech machines with many sensors. 

The first sensor is the chemical sensor. Mosquitoes can detect carbon dioxide gas and lactic acid even from 36 meters away. In addition, some chemicals in our sweat attract the attention of mosquitoes. Yes, if you’re someone who sweats a lot, you’re probably more likely to get mosquito bites.

The second sensor is the visual sensor. Mosquitoes’ vision is not perfect, but good enough to detect a moving object. Also, wearing an outfit that easily reveals your skin color means that mosquito bite spots will appear more clearly. However, when you move, you give the impression of a “bloody and live target”. This means a feast for mosquitoes.

The third sensor is the temperature sensor. Mosquitoes can understand the temperature difference. Thus, it easily recognizes warm-blooded mammals and birds and begins to plot its insidious plans.


When we look at the mosquito anatomy, we see three basic parts. Head, thorax, and abdomen.

All those advanced sensors are in the head. In addition, the eyes, antennae, mouth, and proboscis parts are also located here.

The thorax has two wings and 6 legs. The muscles and heart required for flight are located here.

The abdomen is used for digestion and excretion purposes.

How do they find us?

Mosquitoes can find us easily thanks to their chemical, visual, and temperature sensors. Many living things have the ability to smell chemicals in the environment. In fact, animals can perceive the opposite sex in the environment and be attracted to them through smells called pheromones. Chemical sensors, in particular, are the most powerful sensors to get them to their destination, and there’s not much of a way to prevent it. We all live by taking in oxygen and giving out carbon dioxide. This is a process that we are so accustomed to that we often breathe without realizing it. The carbon dioxide we exhale is perceived as a delicious food smell for mosquitoes.


Even more interesting is the research that Vinageur has done. These blood-sucking creatures can distinguish between sleeping people and awake people. This differentiation process is due to the fact that the carbon dioxide emitted from us is different when we are awake and asleep. And of course, they use their preferences on sleeping targets because they are easier to eat.

Why Is It So Deadly?

A sleeping and sweating human body has been found, releasing copious amounts of carbon dioxide gas. Now it’s time for the feast. Only female mosquitoes have the proboscis necessary for biting and sucking blood. Since males do not have this proboscis, they cannot bite even if they want to. Yes, all the mosquitoes that have bitten you so far have been females! 

Mosquito bites may not only cause itching. While these annoying creatures suck your blood, they can also infect you with viruses. In particular, malaria is responsible for more than half of mosquito-related deaths. The malaria virus, which spread mostly in the African region, caused the death of many lives in a short time. Another deadly virus transmitted by mosquitoes is dengue fever. This virus occurs in some Asian and Latin American countries.


What about Covid-19? No need to be concerned. Research on 1165 mosquitoes collected from the city of Wuhan, China, where the pandemic began, has shown that no mosquitoes carry the Covid-19 virus. Moreover, even when the most suitable environment conditions were created for a mosquito to carry the virus and the same test was performed, it was seen that the mosquitoes could not carry this virus.

Why Does the Bitten Place Itchy?

While the process of putting someone’s needle into your body and drawing your blood may seem scary, it actually does it in the most painless way. There are anticoagulant proteins in the saliva of mosquitoes that prevent bleeding of the bite site. After the bite, this saliva remains in the vein. After a short time, the immune system, which detects this foreign protein, begins to show symptoms such as itching. This itching continues until the immune system destroys the foreign proteins from the saliva.


If you want to learn more about the reactions of our body to foods, we recommend that you take a look at our article ” Why Are Some People Allergic to Certain Foods? “.

References and Further Reading

Craig Freudenrich, P. D. (2001, July 5). How mosquitoes work. HowStuffWorks.

Pflanzer, L. R. (2016, September 8). These are the world’s deadliest animals. Business Insider.

Xia, H., Atoni, E., Zhao, L., Ren, N., Huang, D., Pei, R., Chen, Z., Xiong, J., Nyaruaba, R., Xiao, S., Zhang, B., & Yuan, Z. (n.d.). SARS-CoV-2 does not replicate in Aedes MOSQUITO cells NOR present IN Field-Caught mosquitoes from Wuhan. Virologica Sinica.

Yetman, D. (2020, October 23). Can mosquitoes transmit the NEW coronavirus? What you need to know. Healthline.

Images not cited are used through Canva Pro with a royalty payment.

The proofreading has been done by Özge Arslan and Mete Esencan.

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Mete Esencan

Hello everyone! I'm Mete Esencan. I am a graduate student in the Department of Chemistry at METU. I was planning to establish a platform by combining the research knowledge I gained during my basic science education and the management experience I gained in the METU Chemistry Society, which I was in charge of for three years. For this purpose, in February of 2021, I took the first step and established the OkButWhy, a platform where we can write articles as if to chat about science, art and philosophy. I wish everyone a pleasant reading!

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