Jellyfish — Open Ocean
Quick Fact
Jellyfish have no brain, no heart, and no bones — yet they have survived five mass extinction events.
About This Species
Jellyfish are among the oldest multicellular animals on Earth, having existed for over 500 million years — predating the dinosaurs by hundreds of millions of years. Despite their simple appearance, jellyfish are sophisticated predators with complex nervous systems and remarkable survival strategies. Some species are biologically immortal, capable of reverting to their juvenile polyp stage when stressed. Jellyfish blooms are increasing globally, partly as a result of ocean warming, overfishing, and nutrient pollution.
Why It Matters
Increasing jellyfish blooms are a sign of ocean ecosystem disruption. They can outcompete fish for food and clog fishing nets and power station cooling systems, with significant economic consequences.