Have you ever wondered which animal is responsible for killing the most people?

Perhaps a shark?  Maybe some type of snake or spider? Or maybe some sort of large land mammal like a grizzly bear or a lion?

If you were thinking along those lines, then I’m sorry to disappoint, but the deadliest animal known today is quite a bit smaller than all of those. Believe it or not, found almost everywhere, on every continent except Antarctica, our deadliest animal is the mosquito!

Presenting: The Deadliest Animal. A mosquito.

How is this possible?

Mosquitos are notorious for transmitting diseases. They carry with them diseases like malaria, dengue fever, yellow fever, encephalitis, West Nile virus, and countless others. Acting as vessels for diseases, mosquitoes transmit these diseases to either us, or animals. These diseases can then make us very ill and sometimes even lead to death. It is not actually one type of mosquito that is transmitting all of these diseases, but in fact, it’s several. The most common belong to the genera Aedes (Dengue and Yellow Fever), Anopholes (Malaria and Canine heartworm), and Culex (West Nile, Encephalitus and Avian Malaria).


At more than 1 million fatalities each year, the mosquito is most certainly the deadliest of all animals.

Why They Bite

Mosquitoes need the protein in our blood, or the blood of other animals, in order to lay their eggs.  This means that only the female mosquitoes need blood. In other words, next time you find yourself scratching away at one or more of those incredibly itchy and annoying mosquito bites, you can thank female mosquitoes for that. The male mosquitoes are content living off plant nectar.

The way a female mosquito bites us is by sticking her thin, sharp proboscis into our flesh.  As she draws blood she inserts some of her saliva along with anticoagulants to keep the blood from clotting. This is where the danger lies and gives mosquitos the rightful title of being the most deadly.  In the mosquito saliva there could be viruses and parasites lurking, ready to infect us. These diseases can be deadly, but are not normally transmissible between humans. However, mosquitos are doing an excellent job acting as vectors for transmission of these diseases.


But how exactly do the mosquitos find us?

Mosquitos have several different ways to sense living things so that they can then bite and extract blood. The first of those is chemical sensing. Mosquitos can actually detect CO2 in the air from about 100 feet away. As we and other animals around us exhale, mosquitos are alerted of our presence.

Mosquitos can actually detect CO2 in the air from about 100 feet away.

So maybe we can just hold our breath next time we see a mosquito? Well, it’s not quite that easy. Mosquitos can also detect heat and have visual sensors that can detect color contrast and movement.

It might be a little harder to trick that mosquito!

Although attempting to hide completely from mosquitoes might not work, there are plenty of things we can do to make our lives a little easier and safer, such as:

  • Wear long sleeves  & pants.
  • Put on mosquito repellents that contain DEET.
  • Avoid being outside during dawn, dusk, or late evening.
  • Eliminate stagnant water. It attracts mosquitos & gives them a good place to lay their eggs.
  • If you have a pond, consider stocking it with Gambusia, which feed off mosquito larvae.

As irritating as these insects can be, they have been around for a whole lot longer than us – about 30 million years. So, it seems inevitable that we must learn to exist with them, but it doesn’t hurt for us to have some kind of upper hand to protect ourselves.

Sources: USDA (PDF) | CDC | How Stuff Works

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