Avoid These Incredibly Dangerous Species at All Costs
Danger comes in many forms — some that cause little more than a quick skipped heartbeat and some that land you six feet under. When it comes to dangerous creatures, the world is filled with species that pose a threat to humans.
From a dangerous fish known to attack snorkelers to an unseen parasite that kills more than 200,000 people each year, we've rounded up 25 of the most dangerous species on the planet.
25. Mute Swan
Yes, swans are beautiful and inspire romance — they mate for life — but they are also noisy, obnoxious and might even try to drown you if they perceive you as a threat. Keep this in mind the next time you think about approaching a swan’s nest while you’re casually feeding the ducks during a stroll in the park. Swans are extremely protective of their territory, and they’re far more powerful than you might think.
24. Red Imported Fire Ant (RIFA)
Ants are amazing, impressive creatures. In fact, entomologists E. O. Wilson and Bert Hölldobler even won a 1991 Pulitzer Prize for their non-fiction book The Ants. However, for those without any interest in the insect world, ants are the annoying little biters that ruin picnics and invade pantries. It turns out, some species can also cause widespread medical trauma and economic devastation.
23. Titan Triggerfish
Although sharks and barracudas have more daunting reputations, another sea creature actually poses more danger to divers and snorkelers. Found throughout the Indo-Pacific region, the striking titan triggerfish attracts underwater photographers with its interesting look but is uniquely aggressive and territorial, especially when guarding its nest during the reproductive season.
22. Tropical Rat Flea
Rats are disgusting creatures — yes, even the much-beloved "Pizza Rat" that inspired a brief rebranding for minor league baseball’s Staten Island Yankees. So, what could be even more hideous than rats, which at least feed pet snakes and help out research scientists? Rat fleas.
21. Komodo Dragon
Komodo dragons — basically modern-day dinosaurs — are the only lizards that prey on humans. In addition to isolated fatal attacks, the giant lizards are guilty of severely maiming humans. One attacked movie star Sharon Stone’s husband in 2001, badly disfiguring his foot.
20. Southern Cassowary
The southern cassowary, also known more whimsically as the double-wattled cassowary, is one of the tallest and heaviest birds on Earth. Native to the rainforests of New Guinea and Australia, the birds don’t quite measure up to the ostrich, but they pose a much greater threat. As some signs in Australia caution: "Be Cass-o-wary."
19. Polar Bear
When they’re not starving to death stranded on melting sea ice, polar bears are remorseless predators in a sparse habitat that spans the region north of the Arctic Circle. They can weigh upward of 1,500 pounds, easily more than enough to break the ice.
18. Brown Recluse Spider
Arachnophobia is a common and understandable fear — spiders are creepy! — but most of them don’t cause necrosis like the brown recluse spider. This relatively small spider’s bite contains a dermonecrotic venom, and skin grafts are needed to treat the lesions in certain severe cases. However, you don’t have to be as worried as you might think. The brown recluse isn’t aggressive, and you can live side-by-side with thousands of these dangerous spiders in your home without getting bitten.
17. Reef Stonefish
Although you might have a chance of spotting most marine threats before they harm you, some of the most dangerous aquatic creatures look just like a rock or sand. A master of camouflage, the reef stonefish has the uncanny ability to blend into its surroundings.
16. African Bush Elephant
The largest land mammal on Earth, the African bush elephant is larger than its Asian cousin and can be easily identified by its wider ear flaps, which help the massive animal stay cool in triple-digit temperatures. Elephants’ exceptional intelligence and complex herd dynamics can make their behavior difficult to understand. For an article related to scientist Caitlin O’Connell’s book Elephant Don: The Politics of a Pachyderm Posse, National Geographic used the headline "Why Elephants Are As Ritualistic and Violent As the Mafia."
15. White-Tailed Deer
White-tailed deer might look like cute, harmless wildlife to encounter on a leisurely hike, but their booming population growth has turned them into a nuisance for farmers and a serious danger on roadways. Car accidents involving deer occur more frequently during the fall and early winter, and striking an object weighing more than 100 pounds can sometimes have fatal results for drivers and passengers.
14. Southern Blue-Ringed Octopus
The southern blue-ringed octopus is pretty to look at, but you should resist any temptation to touch it. As Ocean Conservancy helpfully points out, "This golf-ball sized powerhouse packs enough venom to kill 26 humans within minutes." Its bite has one lethal neurotoxin via saliva glands, while its blood contains another neurotoxin.
Unlike lions that live in social groups called prides, the leopard is a solitary animal. Unfortunately, this big cat is more tolerant of human intrusions into their habitat, which places them dangerously close to humans at times. Although attacks are rare, a leopard that is sick, injured or having difficulty finding natural prey due to habitat loss is much more likely to attack a human. They have even been known to hunt human beings. Also, they are nocturnal, so forget about sleeping out under the stars during your safari.
12. Arizona Bark Scorpion
Despite its small size of two to three inches in length, the Arizona bark scorpion has more powerful venom than any other scorpion in North America. Fortunately, it takes up to two weeks for these scorpions to regenerate their powerful venom, so they try to conserve it when possible by clutching their prey and eating it alive.
11. Saltwater Crocodile
The saltwater crocodile actually preys upon humans if humans happen to be around. An encounter is unlikely, but if you’re near crocodile-infested waters, keep your head on a swivel, and don’t step on any lily pads with eyes. These reptiles can grow beyond 15 feet in length and weigh well over 1,000 pounds. They also range far from shore and are capable of swimming through open ocean more than 500 miles at a time.
Sometimes referred to as "superbugs," antibiotic-resistant bacteria have become an increasing concern around the world. According to the CDC, MRSA infected 80,000 people and caused 11,285 deaths in the U.S. in 2011 alone.
9. North American Brown Bear
More commonly known as grizzly bears, North American brown bears can weigh more than half a ton and are "godless killing machines" — at least according to Stephen Colbert’s pundit character on The Colbert Report. Their possible atheism aside, it’s certainly true that hikers fear stumbling upon a mama bear with her cubs, as she is sure to fiercely protect them by shredding any perceived threat into submission.
8. Cape Buffalo
Lions are undoubtedly ferocious, with their sharp teeth and claws capable of inflicting significant damage and swift death, but another animal poses a more worrisome threat across Africa. The cape buffalo might resemble a lackadaisical cow chewing its cud, but this massive bovid can weigh more than 1,500 pounds and possesses a surprising mean streak.
The largest member of the Cervidae (deer) family, a moose is actually far more dangerous than a bear. According to the Alaska Department of Fish and Game, "more people in Alaska are injured by moose than by bears each year." They acknowledge that "most moose charges are bluffs, warning you to stay back," but that does not mean you should think about calling its bluff.
6. Golden Dart Frog
The golden dart frog,also known as the golden poison arrow frog, falls into the category of "pretty colors equals potent poison." This frog has glands beneath the skin packed with 20 times the volume of poison found in other dart frogs, and the terrifyingly potent alkaloid toxin causes prompt damage to the nervous system.
They may look chubby and cheerful, but that’s just the anthropomorphism talking. Imagine planning a once-in-a-lifetime birthday getaway to South Africa and Zimbabwe to see the wondrous Victoria Falls and more. Then, while canoeing down the picturesque Zambezi River on your dream trip, a hippo knocks you and your husband out of your canoe, drags you underwater and breaks your femur. That’s exactly what happened to a Florida woman in 2018 — and she was lucky.
4. Black Mamba
Quentin Tarantino named his lead character in Kill Bill after the extremely deadly black mamba and even featured the snake in the action. Former NBA legend Kobe Bryant also adopted the moniker. This snake can kill an elephant with its venom, so a human is really little more than an appetizer. They are aggressive but also frequently found in close proximity to humans — a bad combination.
3. Box Jellyfish
In the 2011 "Spooked" episode of The Office, Dwight, an amateur naturalist, asks Robert California's son Bert, "I suppose you’re going to tell me the scariest animal is a shark?" Bert responds, "Try a box jellyfish," greatly impressing Dwight. Ranking among the most venomous creatures on the planet, the box jellyfish can have tentacles up to 10 feet long, and it can swim to cover a broader range, unlike most jellyfish that merely float. They also have 24 sophisticated eyes, some with distinct parts — lens, cornea, iris and retina — similar to humans. All the better to see you with, apparently.
2. Schistosoma Japonicum Parasite
Unseen threats are sometimes the most dangerous of all. The schistosoma japonicum parasite can infect many different species, including humans. The parasite spreads when infected humans contaminate freshwater sources, particularly when those sources have certain aquatic snails that can rapidly multiply the parasite and spread schistosomes that are then absorbed by humans through their skin, potentially damaging the liver, bladder and other vital organs.
The thousands of species of mosquito serve as a nuisance to most people, but they pose a mortal danger to millions of people worldwide. In fact, philanthropist Bill Gates has made malaria treatment one of his chief philanthropic causes. According to his Gates Notes blog, malaria "kills more than 600,000 people every year; another 200 million cases incapacitate people for days at a time. It threatens half of the world’s population and causes billions of dollars in lost productivity annually." Unfortunately, the world’s poorest and most vulnerable people have the greatest risk.