Most Dangerous Animals in the USA

Razor sharp fangs, intimidating howls and unrivaled lethality – some of the world’s deadliest animals can be found right in the U.S. Brush up on these dangerous animals before your next adventure, or you may find yourself in a world of hurt!

1. Grizzly Bears

close-up photo of a grizzly bear

Grizzlies are North American brown bears famous for their dominant temperament and daunting size. The colossal creature has humped shoulders and a strikingly-high forehead. Its brown fur is usually silver-tipped, giving the grizzly its namesake grizzled effect.

An adult grizzly towers eight feet high – much taller than the average human – and weighs about 900 lbs. The Alaskan grizzly bear, or the Kodiak bear, is even more intimidating, as it’s the largest living land carnivore, on par with the Polar bear. The Kodiak may reach a weight of 1500 lbs. and grow 10 feet tall.

The Kodiak is lumbering, but other grizzlies are agile and can run incredibly fast – up to 30 mph. Grizzlies sometimes attack humans without evident provocation, but females with cubs are the most aggressive.

Its immense power and razor fangs and claws put it at the top of its league, making it a true apex predator. You will mostly find it roaming the wilds of Alaska.

2. American Alligators

American alligator

The American alligator is the apex predator of the marshlands in the southern United States. It is striking when young – black with yellow banding – then brownish when adult, reaching a phenomenal and petrifying 19 feet.

Unfortunately, just as the rest of the predators here, the main threat to it is man. People have hunted the American alligator for its skin and its young has been sold in droves as pets.

Because of this, the American alligator evaporated from many corners of America where it once abounded.

Finally, after winning legal protection from hunters, the American Alligator made a dazzling comeback. Typically, the beast eats fish, small mammals and birds.

If it is feeling pumped, however, it may devour prey on the scale of deer or cattle.

Unnervingly, both sexes of American Alligator hiss. The male may unleash a roar that carries across massive distances. Beware of the females, in particular, as they may be twitchy when guarding their eggs.

3. Snakes

Adventurers beware: the U.S. is home to some of the deadliest snakes around, so equip yourself with the knowledge to defend against them.

The menacing look of a snake comes naturally – the smooth scaly body, forked tongue and giant fangs are designed to do more than just intimidate.

Most snakes, however, are not that dangerous, and if you leave them alone they won’t harm you. If you tread on or inadvertently corner one, however, you may be in trouble.

Here are the 4 most dangerous snakes in the U.S. Avoid these formidable predators at all costs.

Mojave Rattlesnake


The Mojave rattlesnake is a venomous pit viper that lurks on bare grasslands in the southwestern U.S. The adult Mojave rattlesnake stretches about three feet long and has a distinctive appearance: it has a triangular head, narrow neck and short, black and white banded tail ending in a rattle.

Knowing how to identify a Mojave rattlesnake is a vital skill, as its venom presents a mortal hazard. The lethal species varies in color from gray and pale brown to olive. Like so many dangerous snakes, it is deceptively intriguing. A chain of brown diamonds with light centers and white edges extends along its back.

Some Mojave rattlesnakes pack the tissue-damaging hemotoxins typical of rattlesnakes. Others pack paralyzing neurotoxins that are sneakily destructive, causing no pain until acute respiratory distress kicks in.

New World Coral Snake


The New World coral snake, also known as the “true coral snake,” is an eye-catching specimen, but do not be deceived. Like the Mojave rattlesnake, it is a highly dangerous snake.

Widespread in the southern U.S., the New World coral snake has a narrow head, sleek body and long, pointed tail. Its creepy “snout” is rounded and its eyes are tiny.

Its most distinctive attribute is the narrow yellow rings set between black and red rings. “Red next to yellow can kill a fellow, red next to black and you’re all right Jack,” is a popular jingle that separates the snake from its harmless mimics.

Inclined to burrow, the New World coral snake passes most of its time tucked away in animal tunnels, hollow logs and under rocks. Sometimes, it can be found hanging out in stone ruins. Remember to be aware of these danger zones the next time you set off exploring.

Theoretically, it is in the market for small snakes and lizards, but you do not want to test that theory because the New World coral snake has a tetchy temperament. If accidentally touched, it will strike in a flash. Any bite it inflicts should be taken seriously because it can be fatal.



The moccasin – or water moccasin – is a dark, heavily-built, venomous North American snake, filed as part of the viper family. Semiaquatic, the moccasin hovers in these settings: riverbanks, swamps and sluggish waterways of the southeastern Gulf and Mississippi Valley states.

The adult moccasin usually grows to up to four feet long, but can reach a terrifying six feet long. The moccasin’s color ranges from dull brown to olive or black, with wide black, jagged bands. It also as a distinct flat-topped, triangular head set atop a slender neck that looks small relative to its surprisingly chunky body.

If you find yourself in a tight space with a creature resembling a moccasin, don’t panic. Take a second to check out the eyes. If the pupils are round, it is a harmless water snake, probably more scared of you than you are of it. If the pupils are “vertical” on the other hand, it is a venomous moccasin.

When angry or spooked, the moccasin shakes its tail, throws its head back and gapes, baring its pair of membrane-covered fangs. Even more unnervingly, the open mouth and throat are strikingly white. Hence the reptile’s nickname, cottonmouth.

The cottonmouth can bite underwater. The venom that the reptile releases is acutely toxic – a bite can be fatal to a human victim, making it another dangerous snake that you should never mess with.

Ever gone head-to-head with one of the most dangerous snakes in the U.S.? Tell us your story in the comments below.

Burmese Python


In the Florida Everglades, Burmese pythons can be found scrapping with alligators to sit at the top of the swamp’s food chain. Pythons are also taking out other hefty animals that get in their way.

In 2011, a 16-foot python was found resting after devouring an entire deer. Invasive pythons now maraud the Everglades – they own the area – and they are moving towards the Florida Keys and elsewhere up north.

The snakes were unleashed by irresponsible pet owners into the Everglades, which cover about 4,000 square miles of Florida. They are on the march and on the up because they combine lethality with fertility. A female python can lay 100 eggs, which is tough on the ecosystem.

Since the Burmese python’s takeover, there has been an extremely large decrease in raccoons, opossums, and bobcats. Marsh and cottontail rabbits and foxes have also been alarmingly absent.

The Burmese python sports sharp rearward-pointing teeth that seize its prey, and is one of the largest snake species on earth.

4. Gray Wolf

gray wolf

Also called the timber wolf, the gray wolf may look less imposing than the grizzly, but it is still a force to be reckoned with.

The largest wild member of the Canidae family, male gray wolves may weigh in at just under 100 lbs. The wolf resembles a German shepherd, only with a bigger head, narrower chest, longer legs, and larger paws.

The gray wolf is an alpha predator wherever it roams. While grizzly bears are surprisingly big on berries, gray wolves have an alarming penchant for livestock and, occasionally, humans.

Wolves are bouncing back from a threatened conservation status in the Great Lakes, the northern Rockies, and the Southwestern United States.

5. Great White Shark


Few are surprised to see this name on a list of most dangerous animals in the USA. You have to hand it to the great white shark. Few other creatures on the planet, except saltwater crocodiles, are so terrifying.

The great white shark may be North America’s most commanding alpha predator because it operates in the ocean – a location that automatically puts humans at a disadvantage.

The most feared shark in the ocean, the great white is sometimes called the white death. It grows up to 20 feet long and can weigh almost two tons. The great white is incredibly formidable – capable of short, high-speed pursuits and even breaching -launching itself clear from the water.

In addition, the great white packs large, triangular, blade-like teeth that are serrated along the sides. The super-predator also boasts powerful jaws and the ability to sense vibrations and electrical impulses.

It can also smell, taste, hear and see extremely well. The great white can burst toward prey at speeds of up to 31 mph. Its diet includes seals and even whales.

Despite its negative reputation, sharks rarely attack people. When one does, it is usually because it mistook a diver, swimmer or surfer for a seal or other prey.

One place to see Great Whites is near the Farallon Islands off San Francisco. One company runs a tour []. The usual deal with great white experiences is you get dunked in a cage while your tour operator obligingly dangles tasty, shark-friendly morsels to draw the animals over.

You probably won’t want to go swimming in great white shark-infested beaches for obvious reasons.

If there is any upside to shark attacks from an American perspective, it’s that they mostly seem to happen off the coast of Australia.


Arachnophobia is a serious condition, especially for adventurers, but the most dangerous spiders in the U.S. are enough reason to want to avoid arachnids altogether.

Arachnophobia, the fear of spiders, is one of the most common phobias in the world, and with reason. An adventurer can be mortally wounded by a spider if he tangles with the wrong species.

Here are the most dangerous spiders in the US.

Black Widow


The black widow spider is the common name of any of the species of poisonous North American spiders. The black widow is notorious for the toxicity of its venom to humans.

Its bite unleashes a tiny, yet potent, dose of a neurotoxin that sparks local pain, swelling, and – if you get unlucky – respiratory distress and death.

The widow’s venom is one of the most potent in the animal kingdom, relative to body size. If bitten by several widows at once, your survival chances are slim to zero. The black widow is easily identified – jet-black in color, with characteristic red markings on the underside of its abdomen.

The black widow gets its name from its mating ritual – the much bigger female widow eats the male after mating, probably to suck up the vital nutrients needed for egg-laying.

Black widows occur all over North America, but mostly in the northern, western, and southern regions of the continent.

Brown Recluse


Also referred to as the violin spider, the brown recluse can be found in the western and southern U.S. Its body stretches about a quarter of an inch. On the front half of its body, it sports a dark, violin-shaped design, the “neck” of which is formed by a striking furrow on the midline of its back, and the spider’s six eyes are set in two rows.

The brown recluse’s venom is extremely deadly – it destroys the walls of blood vessels near the site of the bite, sometimes causing a giant skin ulcer. The wound, which may require several months to heal, can kill. Despite its name, the brown recluse has broadened its range into parts of the northern U.S. and beyond.

It rides along with packages in the mail and in vehicles, and may even lurk in your clothing. Its natural home is caves, rodent burrows, and other shielded settings. In buildings, it usually occupies quiet spots like attics, storage areas, and wall or ceiling voids.

Hobo Spider


The hobo spider resembles the brown recluse, but with hairier legs. Again, like a recluse, the hobo’s venom can cause tissue to die at and around the bite site. The wounds can take months to heal and leave permanent scars. Meantime, one of the easiest to identify symptoms of a hobo spider bite is a thumping and persistent headache that medication can’t eradicate.

The hobo spider builds a trampoline-like, funnel-shaped structure of silk sheeting and lurks at the small end of the funnel. Then, it waits for prey to wander into its web.

The hobo spider is the leading cause of serious envenomation in the northwestern U.S. Since its introduction from Europe into the Seattle, Washington area in the 1930s, the hobo has been rapidly expanding its reach. It is common around Salt Lake City, Utah.

Yellow Sac Spider


Pale yellow or whitish, the yellow sac spider sits in silk tubes during the daytime and comes out to hunt at night. Its habitat is surprisingly domestic. It favors houses – specifically the top of walls and ceilings. It also hovers outdoors on foliage.

The “draglines” it leaves while hunting are one of the most common spiderwebs that you may eradicate with a broom or vacuum cleaner. People sometimes unwittingly brush up against them in the dark, to their regret.

The yellow sac spider’s bite is toxic – the venom contains the substance cytotoxin, which can destroy cells much like the venom of a brown recluse.

The common symptoms of a yellow sac spider bite are a stinging sensation, followed by redness and swelling. Sometimes, blisters form and burst. The yellow sac hunts for food – usually insects – at night.

Brazilian Wandering Spider


The Brazilian wandering spider is the most venomous spider on earth. Stretching up to five inches across, the highly aggressive creature has a territorial outlook. It is not native to North America but turns up through hitching rides. It is sometimes called the banana spider because it appears in bunches of the fruit.

When rattled, the Brazilian wandering spider stands itself up on its back legs, showing its striped arms. In severe bite cases, its potent neuro-toxic venom can trigger shock, paralysis, even death, if medical treatment is not received quickly.

You can identify the Brazilian wandering spider by the scarlet hairs covering its fangs. The Guinness Book of World Records ranks the Brazilian wandering spider as the most poisonous spider and the one responsible for the most human deaths.

7. Various Nasty Ocean Dwellers



Do not underestimate stingrays. Stingrays can wreak major havoc for unaware swimmers. Like sharks, stingrays can get everywhere. America proudly boasts its own variety, known as the Atlantic stingray (Dasyatis sabina). These are common along the Atlantic coast of North America from Chesapeake Bay to Mexico, including brackish and freshwater habitats. Atlantic stingrays have much longer snouts than other stingrays. Step on it at your peril. The dangerous fish utilize a poison stinger when feeling threatened.



Like the great white shark and piranha, the barracuda is synonymous with danger, reflected by its fearsome appearance. Barracudas, which you can find on the Atlantic coast of tropical America, are huge.

What’s worse is, they have prominent, fang-like teeth, much like piranhas. They are voracious, opportunistic predators and count on shock tactics and short bursts of speed (up to 27 mph) to catch their prey.

They also have the nasty habit of mistaking snorkelers for large predators. Barracudas duly shadow them hoping to eat the remains of any prey.

Additionally, anything that glints or shines is mistaken for prey by the barracuda. This is dangerous if you are wearing a diving watch or have any metal on you that can reflect the sun. These monsters can cause wounds that require amputation.

Have you ever gone face-to-face with any of the most dangerous fish in the U.S.? Let us know in the comments below.



Piranhas are native to South America, but a few rogue packs call the United States home, too. There have been reports of small groups of the dangerous fish found in U.S. lakes. People have been finding piranha routinely in lakes across the country. There aren’t enough of them to travel in schools just yet, but they are out there.

If you are brave or crazy enough, you could go looking for them at Lake Winnebago in Wisconsin, Lake of the Ozarks in Missouri, Lake St Clair in Michigan, or Tom Bass Park Lake near Houston, Texas. Most of the fish, which are pretty much all teeth, were caught accidentally during summer fishing trips.

Bullhead Catfish


Bullhead and other species of catfish are widely spread in North America. Bullhead croak at you unnervingly, armed with two sets of spines that can pierce your skin and even fatally wound you.

Fishermen unfamiliar with the proper way to handle their catch are prone to being injured by the catfish’s spine. It is unlikely that you will be fatally wounded by a prick from a freshwater bullhead spine, but the wound hurts immensely. If pain and swelling persist, a trip to the doctor is a must.

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About the Author

CM Burns
CM Burns
CM Burns has been a music video director, a cameraman for Nat Geo, has recorded ancient Tibetan chants in India and swum with whales in Baja, California. Currently living in the Philippines you will find him anywhere Adventure happens.
CM Burns
CM Burns
CM Burns has been a music video director, a cameraman for Nat Geo, has recorded ancient Tibetan chants in India and swum with whales in Baja, California. Currently living in the Philippines you will find him anywhere Adventure happens.
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