16 Amazing Jellyfish Facts And What To Do If You Are Stung
August 13, 2024
There are over 3000 species of jellyfish in the waters of our beautiful, blue planet, and new species are still being discovered all the time. These slimy stingers might not be your favorite ocean creature, but they are fascinating! We are going to look at some interesting jellyfish facts, and also go over what to do if you get stung while scuba diving, swimming, or snorkeling.
16 Jellyfish Facts
1. Jellyfish are older than dinosaurs
Jellyfish are some of the oldest living creatures on Earth, with a history dating back over 500 million years! They existed before dinosaurs and have survived multiple mass extinctions, showcasing their incredible adaptability and resilience. Of all the jellyfish facts, this one deserves the number one spot on our list.
2. They are made up of 95% water!
Jellyfish have a simple body structure, lacking a brain, heart, and bones. They are composed mainly of water (about 95%) and have a gelatinous bell-shaped body with tentacles. Despite their simplicity, they are highly effective predators.
Are sea turtles more your thing? Check out: 11 Amazing Facts About Turtles (and How to Tell Them Apart).
3. Jellyfish do not have brains, but they are not simple creatures
Jellyfish do have brains, blood, or hearts - but our jellyfish facts demonstrate there is more to jellyfish than meets the eye. Instead of a centralized brain, jellyfish have a decentralized nerve net. This allows them to detect changes in their environment, such as light, temperature, and the presence of prey. Their nerve net helps them move and react to stimuli.
4.Their tentacles contain tiny, harpoon-like structures
Jellyfish are equipped with tentacles that contain specialized cells called cnidocytes. These cells house nematocysts, which are tiny, harpoon-like structures that inject venom into their prey or potential threats. The venom can vary in potency, with some jellyfish stings being extremely painful and even deadly to humans.
5.Jellyfish can produce light
Many jellyfish species possess the ability to produce light through bioluminescence. This light is generated by chemical reactions within their bodies and can serve various purposes, such as attracting prey, deterring predators, or facilitating communication with other jellyfish.
6.They have a complex life cycle with two different ways of reproducing
Jellyfish have a complex life cycle that includes both sexual and asexual reproduction. They typically start as free-swimming larvae called planulae, which settle on the ocean floor and develop into polyps. These polyps can reproduce asexually by budding, creating genetically identical clones. Eventually, polyps release tiny medusae, which mature into adult jellyfish and reproduce sexually.
7. Jellyfish range in size from 5mm to over 30 meters!
Jellyfish come in a wide range of sizes, from the tiny Irukandji jellyfish, which can be as small as a few millimeters, to the massive Lion’s Mane jellyfish, which can have tentacles extending over 30 meters (100 feet) in length. Their diversity in size is matched by their diversity in shape and color. This is one of the best jellyfish facts to highlight how diverse these incredible creatures are.
8.They can be immortal
The Turritopsis dohrnii, also known as the "immortal jellyfish," has the unique ability to revert to its juvenile polyp stage after reaching maturity. This process, called transdifferentiation, allows the jellyfish to potentially bypass death and start its life cycle anew, making it biologically immortal under the right conditions.
9. They are passive drifters
Jellyfish are planktonic creatures, meaning they drift with the ocean currents. While they can pulse their bell to move vertically and somewhat horizontally, their primary mode of transportation is passive drifting. This can lead to large blooms of jellyfish when currents and environmental conditions are favorable.
Jellyfish featured in this blog. Check them out: 6 Most Venomous Creatures In The Ocean
10. Jellyfish can form swarms that span hundreds of miles
Occasionally, jellyfish populations can explode into massive blooms, creating dense swarms that can span hundreds of miles. These blooms can disrupt local ecosystems, clog fishing nets, and even interfere with power plants by blocking water intake systems. The causes of jellyfish blooms are complex and can include factors like ocean temperature, salinity, and nutrient availability.
11.They are both predators and prey
Did you know that jellyfish are both predators and prey in their ecosystems? They feed on small fish, plankton, and other marine organisms, capturing them with their stinging tentacles. In turn, jellyfish are preyed upon by sea turtles, certain fish species, and seabirds. Some human cultures also consume jellyfish as a delicacy – one of the jellyfish facts you might want to forget about if you are squeamish!
12. Jellyfish have potential uses in medicine
Jellyfish venom and other compounds have been studied for potential medical applications. Researchers are exploring the use of jellyfish collagen in wound healing and regenerative medicine, as it is biocompatible and promotes cell growth. Additionally, jellyfish bioluminescence has contributed to scientific research, particularly in the development of fluorescent markers used in genetic studies.
13.They are found worldwide, including in the Arctic and Antarctic!
Jellyfish are found in oceans all over the world, from the surface waters to the deep sea. They can inhabit a wide range of environments, including coastal areas, open ocean, and even brackish waters. Some species are adapted to extreme conditions, such as the frigid waters of the Arctic and Antarctic.
14. Jellyfish help us monitor the health of marine ecosystems
One of the most relevant jellyfish facts for the present time is how climate change and human activities are believed to influence jellyfish populations. Rising sea temperatures, overfishing of jellyfish predators, and nutrient pollution can create favorable conditions for jellyfish blooms. This makes jellyfish an important indicator species for monitoring the health of marine ecosystems.
15. Box jellyfish can be deadly, but they are also fascinating
The box jellyfish (class Cubozoa) is known for its cube-shaped bell and potent venom. Some species, like the Australian box jellyfish (Chironex fleckeri), have venom that can cause severe pain, cardiac arrest, and even death in humans. Despite their dangerous reputation, box jellyfish are also fascinating for their complex eyes, which can detect light and dark, helping them navigate their environment.
16. Jellyfish symbolize both beauty and danger
Throughout history, jellyfish have appeared in various cultural contexts, symbolizing both beauty and danger. They are featured in myths, literature, and art, often representing the mysterious and enigmatic nature of the ocean. In modern times, jellyfish continue to captivate people’s imaginations, inspiring scientific research, aquarium exhibits, fashion, and even articles about jellyfish facts - like this one. There is even a World Jellyfish Day (3rd November) dedicated to these amazing creatures.
What to do if you get stung by jellyfish
If you get stung by jellyfish, follow these steps to alleviate pain and minimize complications:
1. Get to Safety
Move out of the water to avoid further stings and prevent drowning due to pain or shock.
2. Rinse with Vinegar
Rinse the affected area with vinegar (acetic acid) for at least 30 seconds. Vinegar helps neutralize the venom and prevent further discharge of nematocysts. If vinegar is unavailable, salt water can be used; avoid using fresh water as it can trigger more stings.
3. Remove Tentacles
Carefully remove any remaining tentacles using a pair of tweezers or gloved hands. Avoid direct contact to prevent additional stings. Do not rub the area with a towel or scrape it with sand as this can worsen the stings.
4. Soak in Hot Water
Immerse the stung area in hot water (not scalding) for 20-45 minutes. The heat helps to reduce pain and inactivate toxins. Test the water temperature to ensure it is tolerable.
5. Pain Relief and Medical Attention
Take over-the-counter pain relievers like ibuprofen or acetaminophen to manage pain. Seek immediate medical attention if you experience severe reactions, such as difficulty breathing, chest pain, or severe swelling, as these could indicate a life-threatening allergic reaction.
Always seek medical advice for stings from highly venomous jellyfish like the box jellyfish.
To avoid being stung by jellyfish in the water, you can wear a wetsuit or dive skin to keep your skin covered.
Have we piqued your interest in marine life?
Learn more about the incredible life in our oceans with SSI’s Marine Ecology courses.