What is the deadliest animal in the world? The surprising animal you've already met.

From alligators to hippos to pythons, Earth's animals aren't always the most peaceful, especially wild ones.

Ourworldindata.org says humans have identified over two million animal species; yet, there are an estimated five to 10 million species, including those undiscovered, on the planet.

According to a study from Utah State University's Department of Wildland Resources, "over 47,000 people annually in the United States sought medical attention after being attacked or bitten by wildlife."

What's the one animal that outranks all others in terms of danger, and what should you do if you come across it?

What is the most dangerous animal in the world?

According to a-z-animals.com, mosquitos are the deadliest animals in the world, killing an estimated 750,000 to 1 million humans yearly. With up to 110 trillion mosquitoes on the planet,  the insects can carry lethal diseases like malaria, dengue fever, West Nile virus and Zika virus. There are 16,000 mosquitoes on the planet for every one person.

According to the Centers for Disease Control and Prevention, 435,000 people died from malaria in 2017. This disease threatens almost half the world’s population, and lymphatic filariasis affects “120 million people in 72 countries.”

To avoid mosquito bites, the CDC recommends insect repellent, long-sleeved clothing with sufficient coverage, screens on windows and doors, air conditioning and mosquito nets on strollers or your sleeping and living areas.

The CDC emphasizes the importance of cleaning and clearing out containers that hold water, as these can become mosquito nesting grounds.

Mosquitoes are the most deadly animal on the planet, despite being far smaller than most apex predators.
Mosquitoes are the most deadly animal on the planet, despite being far smaller than most apex predators.

Top 10 deadliest animals in the world

Here are the animals that cause the most human deaths each year, according to Discover Wildlife:

  1. Mosquitos: 725,000-1,000,000 deaths per year

  2. Humans: 431,000 deaths per year

  3. Freshwater snails: 200,000 deaths per year

  4. Saw-scaled viper: 138,000 deaths per year

  5. Assassin bugs: 10,000 deaths per year

  6. Scorpions: 2,600 deaths per year

  7. Ascaris roundworms: 2,500 deaths per year

  8. Saltwater crocodiles: 1,000 deaths per year

  9. Elephants: 500 deaths per year

  10. Hippopotamus: 500 deaths per year

What to do if you’re bitten by a mosquito

Symptoms of mosquito bites include an itchy, puffy red bump, small blisters and dark bruise-like spots, says the CDC. More extreme reactions -- common in children, adults who have never been bitten before and those with a compromised immune system -- consist of swelling, redness, fevers, hives and swollen lymph nodes.

To treat a mosquito bite, wash the bite area with soap and water. Use an ice pack for 10 minutes, paired with anti-itch cream and a baking soda and water mixture to reduce swelling and itching. Do not scratch the bite, as this can cause infection.

If your bite symptoms worsen, it may be infected or you may have contracted a disease. Contact your healthcare provider for treatment and next steps should your condition worsen.

How to get rid of mosquito bites: home remedies you can use to soothe the itch

What is the most aggressive animal in the world?

The Nile crocodile is the most aggressive animal in the world mostly because it considers humans a “regular part of its diet” according to a-z-animals.com. The animal can weigh up to 1,650 pounds and can be found in  26 countries in sub-Saharan Africa. Every year, Nile crocodiles kill hundreds of people, says a-z-animals.com.

Fire ants and hippos make up the second and third spots on a-z-animals.com’s list of aggressive animals. Fire ants often attack for no reason, and hippopotamuses kill “at least 500 people every year.”

Just Curious for more?

Here at Just Curious, we're looking into all of your questions. From "Do lady bugs bite?" to what to bring camping to more information about mosquitos and how to get rid of them, make sure to check out USA TODAY's Just Curious section for more trivia, tidbits and information you might want to know.

This article originally appeared on USA TODAY: What is the most dangerous animal in the world? It's a common threat.