18 most Frightening Animals in North America

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By Jonathan Trent

The diversity in North America’s many ecosystems allows for a wide range of animals to thrive, some harmless to humans and some capable of causing serious damage if provoked. Today, we’re focusing on the latter; here are the 18 most frightening animals roaming the continent.

Grizzly Bear

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In terms of sheer size, grizzly bears are undoubtedly one of the most formidable animals in North America. According to the US Fish & Wildlife Service, grizzlies can weigh up to 600 pounds, making them the heaviest bear on the continent.


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Alligators are perhaps the closest thing we still have to the dinosaurs, with the species dating back around 245 million years. Their piercing eyes, deceptive speed, and mouthful of razor-sharp teeth make them one of the most fearsome reptiles on the planet.

American Bison

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Despite their enormous size, American bison are mostly peaceful animals, unlikely to attack unless provoked. If you do manage to get on their bad side, however, they will charge at you, reaching speeds of around 35 miles per hour in the process. Trust us–you’re not going to survive that!


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The cougar’s agility and speed, as well as its intimidating facial features, make it a truly terrifying animal, and they’re here in the US! To make matters worse, cougars are ambush predators, meaning they hide in the undergrowth, waiting for their prey to unknowingly walk past.

Wild Boar

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You probably wouldn’t expect a wild boar to be capable of inflicting damage on humans. However, their stocky build and potential weight of up to 500 pounds, as estimated by the Animal and Plant Health Inspection Service, makes them a fearsome opponent if provoked.


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Moose are another American species that appear quite placid on the surface, hiding away their darker side until they feel threatened. If they do come under any sort of attack, especially if their young are present, they won’t hesitate to fight back.


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It’s never comforting to hear a venomous animal before you see it. That’s exactly what happens with rattlesnakes, which are characterized by the rattles on the end of their tails. Their bite is just as bad as their bark, too, containing venom that can trigger heart failure in humans. Yikes!

Black Widow Spider

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The black widow spider is infamous across North America, and its name sends shivers down the spines of arachnophobes. Unlike most spiders, it is feared for good reason, as its bite triggers venom 15 times stronger than that of a rattlesnake.


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The wolverine may not be the most physically intimidating animal in North America, but that doesn’t detract from its ability to attack. The species has been known to take down animals much larger than itself, such as deer, with pure tenacity and aggression.

Gray Wolf

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There are few sounds more chilling than the sound of a howling wolf at night. Although most wolves are scared of humans, their pack mentality, sharp teeth, and aggressive stance make the thought of coming face-to-face with one on a North American hike truly horrifying.

American Crocodile

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If you head into the swamps of Florida, locals will be quick to warn you about alligators. However, the American crocodile is larger, more aggressive, and more intimidating, albeit less common. Thankfully, attacks by the American crocodile on humans are few and far between… let’s try to keep it that way! 


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Although it doesn’t happen very often, coyotes have been known to attack humans, so you should always be vigilant in their areas. As with much of North America’s wildlife, coyotes will be even more aggressive if their pups are still young.


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Bobcats aren’t as physically large as cougars, and their cute looks make them appear harmless. However, don’t be fooled by their appearance, as they will display an intimidating level of aggression if they feel as though they are being threatened. 

Killer Bee

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One of the tiniest on this list, the killer bee, officially known as the Africanized bee, came about after a crossbreeding experiment by beekeepers. The bees were originally kept in Brazil before 26 swarms escaped in 1957 and moved north. Killer bees have been responsible for the deaths of over 1,000 people.

Fire Ants

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Red imported fire ants are invasive and aggressive, unafraid to sting humans and their pets if they get close. The National Fire Ant Eradication Program states that multiple fire ant stings can give the feeling that the body is on fire and can even trigger anaphylactic shocks!

Brown Recluse Spider

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The black widow spider may have a more famous name, but the brown recluse spider is capable of doing even more damage to humans if it feels the need. Thankfully, brown recluse spiders use their venom as a defense mechanism and are unlikely to attack unprovoked.

Portuguese Man O’ War

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Just off the Florida coast resides one of the most feared sea creatures, the Portuguese man o’ war. Its lethal tentacles can cause immense pain, even when detached and washed up on the shore. What makes them scarier is that their tentacles can grow to be around 165 feet long, so keep your distance!

Polar Bear

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The last and likely most dangerous on our list is the polar bear. Well-camouflaged and ever-defensive, you don’t want to pick fights with polar bears. They occupy areas in the northernmost parts of Canada, as well as Alaska, where the National Park Service estimates their population to be between 4000 and 7000!