Jellyfish have been inhabiting the waters of all the oceans for millions of years. They are amazing and fascinating creatures, and people are always curious to know different facts about them. They are a bit weird as they do not have any solid material to hold them up and also there is no brain. It is very interesting to know, that a life form can exist as a ball of jelly. The body consist mainly of water and hence it is a delicate creature and will immediately collapse if taken out of water.

The bell shape body, consists of a gelatinous mass, and there are tentacles trailing underneath this body. Most of the 200 species of jellyfish have this basic physical structure, and they come in different sizes and colors. The jellyfish is a carnivore and hunts its prey either actively or passively, depending on the species and swimming abilities. On the underside of its bell body is an opening which serves as a mouth, as well as an opening to expel waste matter from the body. It is a weird truth, that the jellyfish expels waste, from constant place, because it ingests food This mouth directly opens into a gastrovascular cavity, which serves as a stomach, where the food is digested.

Most jellyfish drift in the ocean, with their tentacles spread out to gather food. Some jellies like the box jellyfish is known to be a good swimmer and will actively chase its prey. But in all types of jellyfish the main apparatus for gathering or capturing food, are the tentacles. These tentacles are armed with cnidocytes containing nematocysts, which are stinging cells with venom. The jellyfish has thousands of such cells on each of its tentacles. The jellyfish has a network of nerves which lets it feel certain sensations and take an instinctive action. When a prey is "felt" by the cnidocytes in the tentacles, it fires thousands of nematocysts filaments at the prey. These filaments have barb-like endings which will go and adhere to the skin of the prey. The filaments will then inject the venom, which will immobilise the prey.

The jellyfish has number of arms around its mouth. These oral arms will bring the trapped food to the opening for ingestion. The gastovascular cavity will directly receive this food and start digesting it, with its gastrodermal lining. The nutrients of the food is then passed along to the various tissues of the body, through radial canals, which criss cross the entire length of the body of a jellyfish. The waste is then excreted through the same opening, which sinks to the ocean floor, where its supposed to fertilise the ocean, so that new life can grow.

A group of scientists at the Marine Biological Association in London, have cultivated the Moon Jellyfish in the laboratory to study its feeding habits and document the decisions they make while searching for food. The scientists observed, that the movement patterns of this jellyfish, while searching for food, was similar to more developed creatures like the turtles and basking sharks.
Normen FAdel
Author of the article
writer and blogger, founder of jellyfish .

New of label : Jellyfish Bodies & Feeding

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