Ancient Creatures! Jellyfish are older than dinosaurs! They have been around for over 500 million years, making them one of the oldest living creatures on Earth.
No Brain, No Heart! Jellyfish lack both a brain and a heart, and bones. Instead, they have a simple nerve net to detect changes in their environment, helping them to swim and respond to stimuli.
Mostly Water! Jellyfish are made up of about 95% water, which is why they can seem almost transparent and delicate. Wow!!
Bioluminescence! Many jellyfish species can produce light (bioluminescence), which they use to attract prey or deter predators by confusing them with sudden flashes.
Immortality in Some Species?! The species Turritopsis dohrnii, also known as the "immortal jellyfish," can revert its cells to an earlier stage in its life cycle and essentially start life over, potentially bypassing death from old age. What?!
Jellyfish Blooms: Jellyfish blooms, where large groups of jellyfish gather, can sometimes be so dense that they block shipping lanes or damage fishing nets. They can even affect power plants by clogging cooling intakes.
Some Jellyfish Are Giant! The lion's mane jellyfish (Cyanea capillata) has tentacles that can stretch over 120 feet (36.5 meters), longer than a blue whale, making it the longest-known animal on Earth.
Jellyfish Can Travel Vast Distances! Some species, like the moon jellyfish (Aurelia aurita), can drift with ocean currents across entire oceans, sometimes traveling thousands of miles!
Venomous But Not Always Deadly: Jellyfish stings can range from mildly irritating to lethal. However, not all species are dangerous, and some use their venom primarily to catch prey rather than defend against larger predators. So don't try to hug one.
Surprising Food Source: In some cultures, jellyfish are considered a delicacy and are harvested for food, particularly in East Asia, where they are dried, pickled, or served in salads.
Jellyfish Can Regenerate: Some species of jellyfish can regenerate lost body parts. For example, Aurelia aurita (moon jellyfish) can regenerate its damaged tissue quite effectively!
Jellyfish Can "Sense" Their Environment: Although they lack a brain, jellyfish possess specialized cells called "rhopalia" that help them sense light, gravity, and even the presence of food and predators through complex chemical signals.
Deep-Sea Jellyfish: Some species of jellyfish live in the deep ocean, at depths of over 1,000 meters (3,280 feet). These jellyfish are often bioluminescent and can survive in extreme pressures and temperatures that would be lethal to most other creatures!!
They Can Filter Water: Jellyfish help filter and clean ocean water. As they feed, they consume plankton, and in doing so, they indirectly help control plankton populations in the ecosystem. Jellyfish for the win!
Jellyfish Have Strange Eyes: Some jellyfish species have multiple types of eyes, including "simple eyes" that can detect light and "complex eyes" that form images. The eyes are used to help them orient and navigate!
Jellyfish Can Be Found in Freshwater: While most jellyfish are marine creatures, there are a few species of freshwater jellyfish. Craspedacusta sowerbyi, a species native to China, has been introduced to various regions worldwide and can be found in freshwater lakes and reservoirs!
Jellyfish Can Use Their Tentacles to "Taste" the Water: Jellyfish tentacles have sensory cells that can detect chemicals in the water, helping them to “taste” the environment for potential food or hazards. Cool!
