As the Latin proverb goes, Homo homini lupus – “man is wolf to man,” which is rather unfortunate as wolves are also wolves to men. Sitting in the kind embrace of modern civilization, it’s easy to forget a lineage fraught with fears of bloodthirsty creatures hidden in the dark.

Tool usage and organized social behaviors landed humanity a spot as the apex predator of the animal kingdom across the globe early on in our history, but there are still many creatures that prove a substantial threat under the wrong circumstances. While humans killing humans is a significant source of death around the world, it “only” accounted for about 560,000 deaths in 2016 — a number that pales in comparison to a single entry on the list of deadly animals.

Polar bears

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Most animals attack humans intruding upon their territory as an instinctual act of self-preservation. Though many of these attacks prove deadly, it’s rare that other predators seek out human beings as prey. Polar bears, on the other hand, are one of the few animal species that will attack human beings for food, if desperate. Lacking an instinctual fear of humans due to a lack of natural exposure, polar bears see humans as an easily overpowered small mammal, and attacks often prove fatal.

Emus

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Emus do not prey on humans but are characterized by a curiosity towards people moving in their surroundings as they may follow us simply to observe. Emus have earned a spot on the list as tenacious opponents of human conquest. In the winter of 1932, Australian settlers found acquired lands encroached upon by emu migrations numbering in the tens of thousands. The large presence of emus made agriculture nearly impossible and sparked what was known as “The Great Emu War.” Machine guns, bounties, and organized parties proved no match for the flightless birds, who regularly evaded attacks and left settlers with an awkward truce and miles of barrier fencing.

Funnel-web spiders

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The list wouldn’t be complete without due respect to the many deadly creatures of the Outback or one of the most common human fears. Australian funnel-web spiders are the most toxic species of spiders. These arachnids are attracted to water and are often found near swimming pools. Most attacks result from the aggression of wandering males, and the bite of an Australian funnel-web spider can kill a child in hours or an adult in one day. Funnel-web spiders were a significant cause of death during early human colonization of their habitats, though anti-venom treatments are fast and effective. Since the widespread availability of funnel-web anti-venom, no deaths have been reported.

Hippopotamuses

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“River horses” are aquatic herbivores that live in herds. The dense mammals are so heavy that they can walk underwater. Hippopotamus calves are frequent targets of crocodiles, and adults have been observed engaging in anti-predator behaviors. In combination with the fierce territoriality of bulls, these behaviors make the creatures a substantial threat to wandering and fishing humans, with death tolls ranging from 500 to 3,000 per year. Hippopotamuses are most dangerous when they perceive threats to their young or the females are in heat.

Mosquitoes

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The deadliest creature to human beings doesn’t bear fangs, claws, or a machine gun but, rather, fragile wings and a thread-like proboscis. A 2016 report from the Bill and Melinda Gates foundation showed that mosquitoes are responsible for the largest number of human deaths related to animals. Carrying diseases as diverse as dengue fever and Zika virus, the most lethal disease that mosquitoes spread in the developing world is malaria with approximately 212 million cases in 2015 and 429,000 deaths.