Jellyfish Facts: Everything You Need To Know About Jellyfish!

Jellyfish are gelatinous zooplankton from the Phylum Cnidaria. From an anatomical standpoint they are little more than a sac within a sac. Their body composition is 95% water. They do not have a brain, or even a central nervous system. They lack anything that remotely resembles a skeletal system. Most jellyfish do not even have eyes. Aside from eating, their only interaction with their immediate surroundings is the ability to distinguish between up and down, light from dark, or physical contact. Yet somehow their light sensory abilities allow them to perceive and maneuver around foreign objects.

Facts About Jellyfish: How Old are Jellyfish?

Jellyfish are one of the oldest non-extinct life forms in existence. This should come as little surprise considering they are just one step up the evolutionary ladder from single cell organisms. Jellyfish fossils have been unearthed dating as far back as the Cambrian Period some 600 million years ago. The Cambrian Period predates not only the extinction of dinosaurs but their existence itself. These mysterious creatures will probably be swimming the Earth’s oceans long after mankind is gone.

Facts About Jellyfish: Can You Keep Jellyfish as Pets?

Keeping jellyfish as pets is a new concept in the home aquarium industry. It was, after all, only two decades ago that jellyfish were first exhibited in a public aquarium. Until then even the most knowledgeable experts didn't know enough about jellyfish to keep them alive in captivity.  You can’t just walk into your local pet shop and buy a pet jellyfish aquarium. You can’t order a jellyfish from even the largest online fish suppliers. The idea of keeping jellyfish as pets falls, at least for the moment, in the realm of specialty items. This is probably because jellyfish require an aquarium that was specifically designed to keep these fragile organisms alive and healthy.  There is currently only a single company that produces an affordable desktop jellyfish aquarium fish tank,  JellyfishArt.  JellyfishArt also tank raises their own Moon Jellyfish for Sale to the general public so that you can actually purchase pet moon jellyfish to stock your jellyfish aquarium with.

Jellyfish Fact: Is it Difficult to Keep Jellyfish Alive in Captivity?

Until just a few short decades ago scientist did not possess the technological expertise to keep jellyfish alive in captivity. Jellyfish are 95% water. They would be  liquefied instantly if sucked into a conventional water filtration system. Jellyfish can not be housed in a traditional square aquarium. They will get stuck in the corners and lack the higher brain functioning ability to get out. If there is not a flow of turbulence in the water, they are reduced to the equivalent of a bowl of jello. Keeping a jellyfish in a home aquarium was unthinkable. There was not a single jellyfish exhibit in a public aquarium anywhere in the world.

Facts About Jellyfish: Do Jellyfish Really Glow in the Dark?

Comb jellyfish do not require a fancy light show to produce their very own disco display. They are not, however, bioluminescent. They simply appear to be. Comb jellies are from an entirely different class (Ctenophora) than jellyfish. One of the defining parameters of what constitutes a jellyfish is the way in which it achieves locomotion. True jellyfish do this by expanding and contracting their hydroskeletons to create a kind of primitive jet propulsion. Mobility in comb jellyfish is achieved by the rabid pulsing of thousands of tiny oars distributed over 8 rows of legs extending from their main body. These legs are called combs, hence the name comb jellyfish. 

These creatures propel themselves through the water by beating their combs against the water in sequence. The combs are highly refractive. Even in lower light settings comb jellyfish give the appearance of producing their own disco light show. Scientists speculate that this hypnotic light display acts to entice the natural curiosity of potential prey.

Facts About Jellyfish: What Jellyfish Does Glow in the Dark?

Facts About Jellyfish: What About Jellyfish Stings?

All Jellyfish have specialized organelles called nematocysts. These cells are full of venom and are present on the tips of a jellyfish’s tentacles. The stinging cells are triggered by touch. When triggered, the pressure in the nematocysts builds up to 2000 lbs. per square inch causing a microscopic lance to be ejected administering the jelly venom. A typical jellyfish contains millions of these stinging cells. Jellyfish do not actually attack humans. Their sting is nothing more than an autonomic response. This response serves the dual purpose being a self-defensive mechanism as well as paralyzing a jellyfish’s prey.  

Facts About Jellyfish: Are Jellyfish Stings Deadly?

That depends on which jellyfish you are stung by. Depending on the species in question, jellyfish stings range in severity from imperceptible to human beings to certain death without immediate treatment. Most jellyfish stings are more akin to a bee sting than anything life threatening. It should be noted that each individual reacts differently on a metabolic level to invasive toxins. Bee stings are little more than a minor annoyance to most people but there are those who must seek medical attention due to potentially life threatening allergic reactions to bee venom.

The Sea Wasp holds the World Heavy Weight Championship title in that arena.  The sea wasp is one of twenty species of jellyfish collectively referred to as box jellyfish because they have a box-like rather than an umbrella shaped bell. Sea wasps invade the northern shores of Australia annually. This incursion into shallow waters begins at the onset of the rainy season around November and typically runs through to the end of May.  Some beaches have nets put in place prior to this annual invasion in an attempt to isolate beach goers from these deadly creatures. Other beaches are closed entirely.

Wasp jellyfish are one of the deadliest creatures on Earth. An adult sea wasp carries enough venom to kill 60 full grown adults. Death can occur in as little as 2-3 minutes depending on the number and severity of stings. This is quicker than any insect, spider or snake known to man. Approximately 1,000 people are stung by sea wasps annually resulting in 100 deaths.  

While box jellyfish may hold the title for being the deadliest creature in the world, pound for pound Irukandji jellyfish are even deadlier. For generations, the Irukandji aborigines spoke of a mysterious presence in Australian waters that brings unspeakable pain. Irukandji syndrome was first documented by Hugo Flecker in 1952. There are at least six species of jellyfish capable of producing Irukandji syndrome. The first of these jellyfish, Carukia barnesi, was discovered in 1964 by Dr. Jack Barnes. This jellyfish was smaller than his finger nail. 

Facts About Jellyfish: How do you Treat Jellyfish Stings?

Contrary to popular belief, urinating on a jellyfish sting is not the best emergency medical treatment. In fact, you may only succeed in making the problem worse.

Jellyfish stingers remain embedded in the skin, just like a bee’s stinger. The first step is to deactivate the stingers to prevent additional venom from entering the victim’s system. Dosing the area with vinegar is the best way to neutralize jellyfish venom and prevent nematocysts from being triggered.

Remove the jellyfish stingers. This can be accomplished by rubbing the skin vigorously with sand or scraping the skin with a dull, flat object. NEVER ALLOW your bare hands to come in contact with the stingers.  Use a towel or gloves.

Seek immediate medical treatment. Lifeguards are equipped with emergency first aid kits and the proper training to treat indigenous jellyfish stings. If immediate medical assistance is not available watch the victim for: shortness of breath, wheezing, tightening of the throat, flushed skin, weakness, nausea, or dizziness until help arrives. These may be signs of the onset of anaphylactic shock, which is potentially life threatening.

Facts About Jellyfish: What is the World’s Largest Jellyfish?

The largest known jellyfish species is the Arctic lion’s main jellyfish followed closely by Nomura’s jellyfish off the coasts of China and Japan. The largest lion’s mane ever officially documented washed up on the shoreline of Massachusetts Bay in 1870. Its bell measured 7.5 feet (2.28 meters) in diameter and its tentacles stretched to a length of 120 feet (36.5 meters). There have been claims of larger jellyfish being discovered since then but none have been officially documented. This photo has been circulating the internet lately. It is a fake, probably somebody’s idea of fun playing with their Adobe Photoshop. This pictures a Nomura's Jellfish at 5 times its actual size.