Try to think of an animal that doesn't have a brain, heart and bones.
But it has lived on Earth for over 500 million years! It sounds like it belongs in some kind of science fiction movie, doesn't it?
However, this is a true animal.
You could even see it during a trip to the beach. Meet the jellyfish. On first sight, a jellyfish doesn't look special. It floats through the water as if it were a clear balloon. Many people don't pay much attention to it. However, the more scientists learn about jellyfish, the more surprising it becomes.
Let's start with its body. A jellyfish contains about 95% water. If you remove the water, very little remains. It does not have a skeleton, a brain or a heart. Most animals need these things to survive.
A jellyfish doesn't. It doesn't have a brain, but it has a simple nervous system to tell what's happening around it. This makes it easier for it to locate food and respond to threats.
But somehow this simple organism has survived for hundreds of millions of years. That means that, indeed, jellyfish existed even before dinosaurs did on earth!
Consider this for a moment. Dinosaurs appeared, then vanished! Many animals became extinct. But jellyfish kept floating through the oceans. As if nothing happened.
They are even more interesting with their tentacles. They are long arms that have very small stinging cells. The jellyfish responds quickly, in one millisecond, and it snaps up the small fish or plankton when they approach.
But now the weird bit comes in. Scientists discovered a species called the "immortal jellyfish." It has the ability to regress and grow again when subjected to stress or injury.
Suppose life is tough, and you become young again every time it happens. No wonder scientists find this animal fascinating.
Even today, many mysteries about jellyfish remain unsolved. They are still being studied to gain more knowledge about aging, survival, and life in the oceans.
The next time you see a jellyfish quietly floating in water, don't think of it as another sea creature.
Imagine one of the survivors of nature!
An animal with no brain, no heart, and no bones that has outlived dinosaurs and continues to amaze the world.
