Jellyfish are weird, jelly-like animals with lots of tentacles but no brain or bones or heart or blood! Look at this compass jellyfish my nephews found when they were exploring the rockpools at the beach in Falmouth during the Summer holidays:
So, when I was asked a question about how jellyfish reproduce (make babies) and how they die, I just had to find out the answers…
Jellyfish have existed on Earth for millions of years. They live in the sea and eat small sea creatures, like shrimps and crabs, and tiny sea plants. But did you know that jellyfish are themselves eaten by sea turtles, fish and sometimes by people?!
The lifecycle of a jellyfish involves five stages of development. A ‘grown up’ jellyfish (that looks like a water-filled bag with lots of dangly tentacles) can release eggs into the sea. If these eggs are fertilised by another jellyfish, they grow into larvae which settle on the sea bed and attach to rocks. The larvae then develop into something called polyps, which grow buds that can ‘pop’ off to make baby jellyfish. These ‘babies’ (which are known as ephyra larvae) then grow into adult jellyfish and the whole lifecycle can start again!
Some kinds of jellyfish only live for a few hours and others live for several months. And like other animals, jellyfish can die for various reasons: for example, they might be eaten by other creatures, catch diseases, get hurt or damaged, or be washed up on beaches.
If you want to find out more about these amazing animals, take a look at the jellywatch website, which has some fun facts about jellyfish! You might also enjoy this short video of jellyfish by the National Geographic.
I’d like to thank Sarah and her children and Meg for the brilliant jellyfish question; and to share this fantastic drawing by my eldest nephew of the compass jellyfish he found!