Giant Jellyfish
Come and Meet the Giant Jellyfish
Giant jellyfish, also called Arctic Lion's Manes, have been on this earth for a long time. They first made their appearance in the oceans about 650 million years ago – that was even before dinosaurs roamed the earth. There are healthy populations of jellyfish in many areas of the world, still. Jellyfish bodies are made up almost completely of water, and they have no blood, no heart and no brain. They are considered to be a very primitive and simple life form.
Scientists have discovered that different species of jellyfish can discern dark from light, and can catch the movements of prey in their vision field. No one has been able to explain why “eyes” work without a brain behind them, but theirs do. Scientists can learn a great deal about vision by studying the role our brains play in processing input.
The Arctic Lion's Mane is a predator, as are most other jellyfish. It captures, kills and then eats other living animals in the waters where it lives. And what does a giant jellyfish eat? Mainly plankton, fish and other jellyfish. Usually the giant jellyfish doesn't have to swim to catch its prey – it's usually delivered to him.
An unsuspecting fish swims into the tentacles of the giant jellyfish, which are almost invisible in the water. The tentacles are laced with stinging capsules, and they inject a poison into any fish that wanders into the tentacles' reach. Giant jellyfish can hunt down other jellyfish and eat them for food as well.
If a human is stung by a giant jellyfish, it could prove to be fatal, but only if enough poison is absorbed into the body. Their venom can cause the muscles around the lungs to become paralyzed, and thus the victim could die. But outside of Japan, most humans have never seen a giant jellyfish. Many of them live in Arctic waters.
Divers in the Sea of Japan are delighted when the swarms of giant jellyfish return to their waters every year. The fishermen of the area see them as invaders, however. Every year, the giant jellyfish cost the fishing industry thousands of dollars, by sliming, poisoning and crushing other fish in the catches, and by destroying nets.
The giant jellyfish is surprisingly lovely to watch, as it makes its way across the surface of the ocean, trapping prey in its tentacles. It doesn't seem like a true predator, but it most certainly is.
Each of the giant jellyfish's unique features, from the sacs that maintain its balance to the sensory organs that let it know prey is near, is a vital piece of the puzzle that is its life. Any phase of creature that had these features less than fully developed would have become extinct. So then, it probably is true that giant jellyfish have always been giant jellyfish.