Composition
Jellyfish are made up of at least 95% water, with only about 5% solid matter.
Lifespan
Jellyfish lifespans vary by species, with some living only a few days, others up to a year, and a few living up to 20 years.
Immortality
The Turritopsis dohrnii species of jellyfish can essentially become new again when threatened by undergoing cellular transdifferentiation.
Predation
Some jellyfish can startle predators by producing bright flashes of light, releasing a glowing tentacle, or sending thousands of glowing particles into the water.
Tentacles
While jellyfish tentacles are indeed slippery, they can sting other jellyfish and themselves if they come into contact.
Age
Jellyfish are older than dinosaurs, with some scientists believing they may have existed as far back as 700 million years ago.
Edible
Some species of jellyfish are edible and are used as an ingredient in various dishes.
Body systems
While jellyfish lack complex systems like circulatory and respiratory systems, they do have a simple nervous system that allows them to respond to stimuli.
Size
Jellyfish can range in size from a few centimeters to over two meters.
Jellyfish have a complex life cycle involving both sexual and asexual reproduction.
Many jellyfish species are bioluminescent, meaning they can produce their own light.
Ecological Importance: Jellyfish play important roles in marine ecosystems, both as predators and prey.