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Feature Creature - Basking shark

Credits: Andrew Pearson

What a spectacular creature - it's the BASKING SHARK! These huge marine animals are the largest fish to be found in UK waters, and despite their huge gaping mouth, gigantic body size and fearsome shark relatives, they are gentle, harmless grazers. 

Fantastic facts:


*Life span: No one really knows    *Super powers: amazing migration of thousands of km


*Favourite foods: plankton, tiny fish and invertebrates     *Enemies: orcas, tiger sharks, boats


*Young: pups are born fully developed, measuring up to 2 metres!


*Latin name: Cetorhinus maximus (ketos = marine monster, rhinos = nose, maximus = greatest)


But what are these animals and what can they do? Basking sharks are:


Filter feeders


Basking sharks are most famous for their unusual feeding habits. Their slow surface feeding behaviour even gave them their name, as people used to think they came to surface to bask in the rays of the sun. In fact, they're searching for microscopic plants and animals called plankton which grow and multiply in the sunlight at the surface of the water.



Using specially adapted gills, basking sharks take in huge amounts of water - around 1,000 tonnes an hour - and filter out a nutritious soup of tiny animals. Basking sharks do have teeth, but they are only a few millimetres in length and don't seem to have any use for adults.


Big fish 


Only one other fish in the world grows larger than the basking shark - the well named whale shark (also a filter feeder). Adult basking sharks are thought to grow to around 7 metres long, but the largest ever recorded back in 1851 reached over 12m and weighed an estimated 17 tonnes! Large animals like these are becoming rare as fishing and hunting intensifies, and the average size of basking sharks recorded today has decreased to around 5m. 


Summer visitors    


Basking sharks regularly turn up along UK coastlines during the summer as they follow the water currents carrying blooming plankton around our islands. They often come quite close to the shore and will happily swim alongside boats and even divers! Look out for them anywhere along the west coasts of England, Wales and Scotland, all around the Isle of Man and the coast of Northern Ireland from May onwards.




Little understood


Despite their size, regular summer visits and gentle, tolerant nature, very little is really known about the life of the basking shark. It is thought that they migrate in winter and spend long periods of time at great depths in search of deep-dwelling plankton when sunlight levels are low. No one is really sure exactly where they all go and why, how long they live, how they reproduce or how many young they have.  


Find out more about how The Wildlife Trusts are trying to help and understand these fish by visiting our Basking Shark Project webpages. You can even download a fact sheet all about them. And watch the amazing video below to see a feeding basking shark in action off the Cornish coast.


Images: Basking shark at surface by Gillian Day / Basking shark and snorkeler by Annabelle Lowe