11 Insane Facts About Box Jellyfish, The Most Venomous Marine Animal

It's not surprising that the world's deadliest creature lives in Australia, since the continent is home to some extremely scary animals and insects. But this creature, which could easily kill you within minutes, is not a spider, a snake, or a shark. In fact, it doesn't even have teeth. It's a box jellyfish. Although this species of jelly can be found in warm waters all over the world, and many of them are poisonous, the box jellies of Australia take the title as the biggest, baddest, and most lethal.

Chironex fleckeri is officially known as the most venomous marine animal, and one sting from a tentacle can bring on extreme pain, shock, and even heart attack within minutes. Scary box jellyfish facts also include stories of victims drowning after they were unable to make it back to shore. Although most Australian beaches feature large yellow signs warning of the dangerous jellies in the water, people continue to get stung and die every year.

So, is it safe to go into the water? Yes and no. Box jelly populations around the world are increasing, leading to more encounters with humans. Here's what you need to know about the deadly box jellyfish to say safe at the shore.

  • People All Over The World Die From Box Jelly Stings Every Year

    People All Over The World Die From Box Jelly Stings Every Year
    Photo: Guido Gautsch, Mithril / Wikimedia Commons / CC BY-SA 2.0

    It's hard to determine exactly how many people die every year from box jellyfish stings. Many of the countries close to waters where box jellies can be found don't require death certificates, and that makes keeping track of how people died extremely difficult. Also, deaths from box jellies are often attributed to something else, like drowning or an everyday heart attack.

    The National Science Foundation believes at least 20 and as many as 40 people die every year in the Philippines due to box jellyfish stings, and that doesn't include the amount of people who are stung but survive. To put those numbers into perspective, compare them to shark statistics. An estimated three people die in Australia every year from shark attacks; worldwide deaths range from about five to 15.

  • Box Jelly Stings Can Attack The Skin, Nerves, And Heart

    When a box jelly wraps its tentacles around its victim, its cells react with chemicals on the victim's skin, prompting tiny darts to release. The darts pierce the victim's flesh and shoot venom into their bloodstream. Within minutes, the victim's blood pressure rises rapidly, their head begins to pound, and their heart starts beating rapidly or stops entirely. People that have been stung can also go in to shock from the severe pain, and may drown if they are unable to swim back to shore.

    As long as the jelly's tentacles stay in contact with the victim, venom will continue to be released. How serious at attack can be depends on the size of both the jellyfish and the victim. Because the venom of the box jelly can attack the skin, nerves, and heart at the same time, under the right circumstances, a sting can be fatal.

  • Box Jellyfish Stings Might Trigger Suicidal Thoughts

    Mark M. Whelan has been stung by a box jellyfish, and lived to tell the tale. He related how he crossed the path of the creature in Gordon's Bay, Australia:

    "The pain attacks your body at a speed that is so fast it cannot be measured. Already your lungs are paralyzed and your stomach is turned upside down. Simultaneously your tongue is trapped and quickly dries out, while your jaw slams shut and your eyes squeeze tight. Your ears go deaf. Your muscles tense in an attempt to combat the pain; then they release succumbing to its awesome power...

    You are defeated without having the chance to put up a fight. It's almost impossible to swim, as a sense of calm courses through you body informing you to just breath in the warm water and the pain will go away...

    For forty eight hours of insanity and the fear of the continuous suffering I was then finally able to summon the strength to pick myself up and get to a hospital."

    Whelan isn't alone in experiencing dark thoughts after a box jelly sting. Doctors report how victims are often consumed by anxiety and beg them for death.

  • Immediately Seek Help If You Or A Companion Are Stung

    If you are swimming alone and are stung by a box jellyfish, it's crucial to find help as soon as you can. You can quickly go into shock or have a heart attack and not be able to return to shore on your own. If you are with a companion who gets stung, keep them calm and help them get out of the water as soon as possible. Once the victim is out of the water, it is extremely important to neutralize the stinging cells from the jelly's tentacles by pouring vinegar over them. In tropical areas where box jellies are common, many lifeguards will have vinegar handy, and it is said to be the only recommended remedy.

    Depending on how severe the sting was (and where on the body the victim got stung), antihistamines, painkillers, and the application of ice may be adequate to deal with the pain. However, more extreme cases will need antivenin to counteract the venom, and that is only available from hospitals or paramedics. Obviously, if a victim is in cardiac arrest or shock, more extreme treatment is needed. Emergency services should be alerted and CPR given as necessary.

  • The Most Dangerous Box Jellyfish Live In The Pacific

    Box jellyfish don't like cold water, so they can be found hanging out in warmer waters all over the world. Many of these jellyfish are not poisonous. However, the most venomous, and therefore the most dangerous, live in the oceans around Australia and the Indo-Pacific. Chironex fleckeri stays mostly in the waters around Australia, and is the largest and deadliest of all the box jellyfish. In fact, it's considered the most venomous of all the marine creatures on Earth.

    Box jellyfish populations have spiked in recent years, possibly due to climate change, spillage of fertilizers that deplete oxygen in oceans, and overfishing. Since fish are the primary predators of jellyfish and those factors kill off fish, box jellyfish are finding it easier to survive and reproduce.

  • Unlike Other Jellies, Box Jellies Can Move On Their Own

    Unlike Other Jellies, Box Jellies Can Move On Their Own
    Photo: Peter Southwood / Wikimedia Commons / CC BY-SA 3.0

    Unlike most jellyfish, which get around by simply letting the currents take them where they will, box jellyfish can swim. They are able to physically propel themselves through the water and can reach swimming speeds of about four miles per hour. That may not seem that fast, but compared to drifting aimlessly, box jellies are pretty speedy.

    Being able to move however they want also allows box jellies to hunt for food and travel elsewhere if prey becomes scarce. By swimming, box jellies can evade predators such as fish and turtles and escape dangerous currents that could potentially harm them as well.