The Specials of June. The Paleozoic Era(The Cambrian Period) Jellyfish

Jellyfish, sometimes known as true jellyfish, are a class of cnidarians found in every ocean of the world from the surface to the seabed. Most are free-swimming, but some are sessile and grow fixed to the seabed. Because jellyfish can't swim against a current, they are classed as planktonic animals - even when they're the size of the huge lion's mane jellyfish, which can grow to over 35m long. Box jellyfish and the Portuguese man o'war are not true jellyfish, although they are related to them.



Delicate and exquisitely coloured, common jellyfish gently drift with the ocean's currents. They’re also known as moon jellies. They have almost translucent saucer-shaped bodies with four bold purple-coloured circular reproductive organs at the centre. Despite their seductive appearance they are formidable predators, feeding on molluscs, crustaceans and worms. Their food is either trapped in the flowing mucus which covers the jellyfish's bell and passed to the oral arms by tiny hairs, or it is actively hunted using stinging tentacles. The stings are not powerful enough to penetrate human skin, so we cannot feel them. Occurring in huge numbers, these are the most common jellyfish found around British coasts. They are also prevalent in the Atlantic, Pacific and Indian oceans.