The jellies have an image problem. No blood, no bones, no heart - these pulsating umbrella-shaped marine animals make the news for all the wrong reasons. They knock out power plants, shut beaches, sink boats and wipe out fish stock.¹

With a mere one thousand nerve cells and no brain, jellyfish are one of the least intelligent animals on the planet. But researchers have discovered the Caribbean box jellyfish is smarter than it looks. No bigger than a fingernail, it can learn to spot and dodge obstacles.

"For neuroscienceScience looking at the nervous system and the brain. ," says marine biologist Anders Garm, "this is pretty big news." The research may help scientists understand memory and treat dementiaA syndrome associated with memory loss and other declining brain functions. . And it shows what can be done without a complex nervous systemThe brain, spinal cord and network of nerves sending messages between the brain and the body. .

Sea jellies have existed for over 500 million years, before the dinosaurs and longer than any other multi-organ animal. There are thousands of species, from microscopic gloop to the Lion's Mane, with tentacles extending up to 36.5 metres. In groups, they are called a smack or a smuck.

And some have remarkable abilities. During the polyp stage of their complex life cycle, they clone themselves into enormous jelly blooms. Polyps grow into medusae with a gelatinous bell and tentacles. But a species called the immortal jellyfish can reverse the process - the only animal that can, in theory, live forever.

Some have lethal weapons. Globally, jelly stings kill between four and five times more people than shark attacks. The Australian box jellyfish is the most venomous marine animal, and its stinging cells move faster than anything in the animal kingdom.

But these curious critters may also help us heal. Jellyfish repair themselves without scarring. Researchers have used tentacle extract to stimulate cell growth in humans, and this super goo may have a role to play in cancer treatment.

And one jellyfish has even won a Nobel Prize.² A special protein in Aequorea jellies makes them glow green. Scientists inserted this bioluminescent molecule into human DNA. It made it possible to track genes and the movement of cells around the body. Expert Charles Mazel says its contribution to science is "incalculable".

But is intelligence one of its superpowers? Box jellyfish don't just float through life. They can learn, remember, and use their 24 eyes and hair-trigger sting cells to hunt their prey. Impressive for a brainless creature that is 95% water.

Scientists have discovered signs of intelligence in unexpected places, from fungal spores to the roots of trees. Slime mould makes decisions as it hunts down bacteria. And trees use fungal networks to communicate about drought and disease.

However, others argue that intelligence is a human superpower. "Sitting on your shoulders is the most complicated object in the known universe," says theoretical physicist Michio Kaku. Almost 100 billion neurons, each connected to 10,000 other neurons.

And this super brain allows scientists to ask important questions about the primordialExisting at or from the beginning of time. origins of intelligence.

Yes: Learning without a mind is a neat evolutionary trick. They have survived every mass extinction by keeping it simple, growing big without wasting energy on heavy-duty organs like brains.

No: This research confirms growing evidence that intelligence is widespread across the natural world. It is not extraordinary or a jelly superpower, but it is much older than previously thought.

Or... Sea jellies are not just one trick superheroes. They have deadly venom, self-healing skin, the ability to clone themselves and turn back the clock. They glow in the dark and have 360-degree vision.