Jellyfish are unique and fascinating creatures of the ocean. They have been around for more than 650 million years, even before dinosaurs.

Jellyfish are 98 per cent water and are also known as jellies.

Jellyfish have two layers of skin and between these two layers is a jelly like substance called mesoglea, which jellyfish get their name from.

They are the animals without any eyes, ears, brain, heart, blood, bones and scales. The only opening in a jellyfish is the mouth, which has hanging tentacles for feeding. The mouth is located right under their umbrella. They also use the same opening to get rid of wastes.

Jellyfish can range in size from peas to seven feet in diameter. Jellyfish cannot swim fast and have no teeth but are one of the dangerous marine creatures.

Hunting style

Jellyfish have long, stinging, poisonous tentacles that they use to catch their food. The feeding tentacles have tiny little capsules called nematocysts. Poison is sent out through the nematocysts to kill their prey. When prey touches the tentacles, poison is automatically injected into them and the prey becomes paralysed. The tentacles then transport the food they killed to their mouth before devouring it.

Jellyfish are beautiful but extremely harmful creatures of the deep. Their poisonous sting can also kill humans.

Favourite food

Jellyfish are fish-eating animals that float in the sea. There are various types of jellyfish with different shapes. The most common jellyfish are the bell-shaped jellyfish with long tentacles hanging down. These jellyfish feed with the help of their tentacles. But the feeding habit of the upside-down jellyfish is quite different. These types of jellyfish are actually more like plants. They also go through process of photosynthesis to make their own food from light energy. So they need a lot of light to sustain life.

Their home

Jellyfish live in the oceans all over the world. They can even be found in freshwater. Some jellyfish are avid swimmers, while others mostly drift with the currents. Only some species of jellyfish live in freshwater. It is quite hard for jellyfish to move forward. There is a ring of muscles around the base of their umbrella. In order to move, the ring of muscles have to contract squeezing the water out of the umbrella which propels them forward.

Lifecycle

Jellyfish goes through several stages during their lifecycle. Most of the jellyfish have both male and female organs. So they can reproduce by themselves. In their life process, adult jellyfish fertilises an egg and drops it on the sea floor. The egg turns into a polyp. In this polyp, tiny jellyfish are stacked on top of each other to form a cylinder of jellyfish. After they mature, one by one the top leaves and beco-mes free to explore the oc-ean life. — Compiled by Merina Pradhan