Wildlife
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.
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Lethal tentacles
The box jellyfish is as fast as an Olympic swimmer with 24 eyes.
The box jellyfish is as fast as an Olympic swimmer with 24 eyes.
Deep sea jelly
A metre-wide big red jellyfish is discovered deep in the Pacific Ocean.
A metre-wide big red jellyfish is discovered deep in the Pacific Ocean.
Discover the other animals and plants that lived during the following geological time periods.
Jellyfish or jellies are the major non-polyp form of individuals of the phylum Cnidaria. They are typified as free-swimming marine animals consisting of a gelatinous umbrella-shaped bell and trailing tentacles. The bell can pulsate for locomotion, while stinging tentacles can be used to capture prey.
Jellyfish are found in every ocean, from the surface to the deep sea. A few jellyfish inhabit freshwater. Large, often colorful, jellyfish are common in coastal zones worldwide. Jellyfish have roamed the seas for at least 500 million years, and possibly 700 million years or more, making them the oldest multi-organ animal.
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Ediacaran period
Cambrian period
Ordovician period
Silurian period
Devonian period
Carboniferous period
Permian period
Triassic period
Jurassic period
Cretaceous period
Palaeocene epoch
Eocene epoch
Oligocene epoch
Miocene epoch
Pliocene epoch
Pleistocene epoch
Holocene epoch