15 Deadliest Beach Creatures

Keep away from any of these 15 deadly creatures when you next visit the beach.



1. Portuguese Man-of-War Jellyfish


Not a true jellyfish, the Portuguese Man-of-War is a siphonophore – a colony of organisms living together. Found mainly far out in the sea, it can be seen swarming or floating with thousands of organisms grouped together. Dermochelys coriacea, commonly called leatherback sea turtles, feed on these sea creatures. In fact, it is their favourite food. Sharks can be attracted to the turtles and mistake a human swimmer or surfer as a turtle. It’s safer on the beach if you see jellyfish in the water. Nematocystic toxin from the Portuguese man-of-war is considered to be ¾ as powerful as that of a cobra.


2. Marbled Cone Snail


The Marble Cone snail shell looks beautiful but the sea creature inside is deadlier than any other possible beach inhabitant listed here. One drop of venom could kill 20 or more people. Found in warm, tropical salt water, if you find one, don’t touch it.  A sting immediately begins showing symptoms or the onset may be days later. The intense pain, numbness, swelling and tingling-feeling can result, in severe cases, muscle paralysis, respiration shut down and vision changes or death. It is fortunate that only 30 people have been killed by envenomation because there is still no anti-venom available.


3. Sea Snakes


Ocean-going trawlers are where most sea snake bites occur since the snake can be hauled in along with desirable catch. Most people think these sea creatures can’t bite but their short fangs, less than 4.5 mm can still pierce human skin. They are also capable of opening their mouths wide enough to consume a huge prey so even a small sea snake can grab a human thigh.


4. Common Cone Shells


The marine snail which inhabits cone shells are found in reefs all around the globe. Their victim-immobilizing venom cause their pray to become paralyzed. Over time, there have been 30 or more recorded human deaths from this venom. Fortunately, medical research has found this venom very helping in pharmacology research. However, there has yet been no antivenom developed for the cone snail stings.


5. Stonefish


The Dornorn, commonly called the “stonefish” is among the most venomous beach creatures on the planet. Named for its appearance, this fish’s coloration makes easy to mistake for a real stone when wading. Mainly in the Pacific and Indian Oceans, it inhabits shallow waters in the tropics. The dorsal fins contain a row of toxic-filled spines. Those who have experienced the envenomation and lived describe it as the worst pain known to mankind. It can cause shock, paralysis and tissue death. Medical attention must be reached immediately. It can cause death to people within a couple of hours. It’s sole beneficial use is as an extremely tasty, okoze sushi, eaten in Japan.


6. Box Jelly Fish


Box jellyfish, known commonly as sea wasp, is probably the most dangerous beach creature listed here. The creature’s tentacles contain tiny nematocysts packed with powerful venom which stick to victims.  Considered by most the most horrible creature to be stung by, victims have been known to pass out in pain yet continue screaming from the venom’s effects. In 1884, documentation confirms the first recorded human victim and it has since killed over 5,500 people. Who knows how many died before records were kept?


7. Blue-Ringed Octopus


A Blue-Ringed Octopus, athis golf ball sized sea creature has enough venom to kill as many as 26 people within minutes. Considered one of the most venomous animals in the world, no anti-venom is known. The bite may first seem harmless but then the potentially-fatal neurotoxins begin their work to cause numbness, muscle weakness, respiratory failure and death. Watch out around the Pacific beaches from Australia to Japan.


8. Fire Ants

Found typically building nests in sandy soil, fire ants live along the beach and other areas in large mounds. They normally feed on nearby plants and small insects. If disturbed by a person, the fire ants scurry to sting and protect their queen. A few stings are only annoying, unless a person is allergic, and they can be treated at home. But if a large swarm of fire ants sting, death can ensue. In fact, about 150 deaths per day occur as well as untold crop damage, qualifying this as one of the deadliest beach creatures.


9. Asian Hornets


This huge hornet can reach three-inches in length. Just 20-30 Asian hornets can invade and kill and entire hive of honeybees. While the sting is generally not lethal except for allergic reactions, there are four special aspects to the venom:

a: Its sting contains more acetylcholine, an enzyme causing pain, than any other stinging insect.
b: An enzyme in the venom dissolves living human tissue.
c: At least eight different chemicals are contained in the venom which then produce another chemical to attract other hornets to a victim.
d: As with all hornets, it has the ability to sting repeatedly.


10. Cat Fish


Don’t mess with the catfish because of the barbed spines sticking out from the back and side fins. Known for whisker-like sense organs around the mouth, many people think that the they are harmless but in fact they are very dangerous. The spine’s sting, causing pain, can even lead to death in exceptional situations. The spine toxin remains active even when fish are frozen, so be careful.


11. Flower Urchin


Toxopneustes pileolus, the flower urchin must be handled with great care due to the long spines which are covered with flower-like venomous pinchers, called pedicillariae. The toxin can cause paralysis and it has been documented to have killed humans in Japan.


12. Great White Shark


This exceptional large shark of “Jaws” fame lives in coastal waters in all the world’s major oceans. Reaching up to five tons and 6 meters in length, this fish is a real predator and the only surviving species of the genus. While they don’t intentionally prey on humans, they tend to “test bite” anything which looks like it could be prey and leads to a number of human fatalities each year in the U.S. During the past century, more people were killed by Great White sharks than dogs.


13. Saltwater Crocodiles


It’s pretty scary to realize that a deadly beach creature can kill an animal as large as a water buffalo. The deadly attack, known as the “death roll”, occurs when the prey is grasped firmly and the saltwater croc begins to roll in the water or on land. In one minute or less, a healthy, spirited one-ton horse can be killed. The crocodile has the ability to travel over land with amazing speed and in the water they are dolphin-quick.


14. Malaria


Malaria is caused by the parasite genus Plasmodium, carried by the Anopheles species of mosquitoes. This parasite has caused half of all human death since records began.


15. Candiru


A naked or loosely-clothed bather can experience the candiru entering one of his or her body orifices such as the vagina, rectum, or penis. If it enters the urinary tract, the fish’s opercle spines make surgery necessary for removal. Perhaps the fish mistakes human urea for water expelled from gills; never urinate in the ocean since this practice may attract this deadly beach creature to enter the urethra. If removal from the human body is not performed, an infection is almost certain to result and this can easily become deadly.


Jo Dennis
About me

Hello i'm Jo, Director of Simply Beach. I love writing about gorgeous swimwear, fashion, beauty and holidays in the sun.


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July 30, 2011

The marbled cone snail isn't harmful to humans at all - http://en.wikipedia.org/wiki/Conus_marmoreus

Although this article is okay, there are other points which could be seen as contentious....like the 'more people killed by great whites than dogs in the US' fact. I would sure love to see your source for that.

August 11, 2011

Great Whites have killed more people than dogs?

This flagrantly untrue piece of information (which should have been obvious to anyone with a lick of sense) makes me wonder how much of the rest of this is bullcrap.

mouth hug
June 6, 2012

150 deaths per day from fire ants?? more like 15 every year.

August 23, 2012

So many inaccuracies here, fire ants do not kill 150 people a day, that is ridiculous, and catfish like the red tail pictured certainly are not found by the beach. Whoever recommended this amateur site to stumbleupon should be shot! Sort it out, spreading misinformation via the internet is a disease.

December 18, 2012

Candiru are native to the Amazon River, but that's it. You don't really need to worry about them if you're swimming in the Pacific.

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