Basking shark
Cetorhinus maximus
IUCN Status:Endangered
What do they look like?
As filter feeders, they're highly recognisable by their large open mouths with gill rakers visible. Their grey skin is mottled and their large mouths make them appear 'top-heavy' despite their sleek bodies.
Where can they be found?
Usually off western coasts, often at the surface
Did you know... The teeth of basking sharks are no more than 6mm in length, but they have six rows at the top and nine at the bottom - that's 1,500 teeth in total!
Key facts
The basking shark is often described as a gentle giant, slowly cruising along the sea’s surface with its enormous mouth open wide as it filters the water for plankton. Despite their size, they are completely harmless to humans. These giants appear seasonally in UK waters, following the spring and summer plankton blooms that draw them close to shore. On calm, sunny days, they can often be seen “basking” just beneath the surface; a behaviour which gave the shark its name.
When feeding, a basking shark can swallow an astonishing volume of water - the equivalent of two Olympic‑size swimming pools every hour. As the water passes through their gill rakers, tiny plankton are trapped and consumed, making them one of the ocean’s most efficient filter feeders.
Basking sharks often reach ages of around 50 years, and they hold the title of the second‑largest fish in the world, surpassed only by the whale shark.
Fully grown individuals can reach up to 12 metres in length, roughly the size of a London bus - though far more graceful. Their slow, deliberate movements and immense size make them one of the most awe‑inspiring sights in British waters.
| IUCN status | Endangered |
|---|---|
| Length | 12m |
| Weight | 4,500kg |
| Speed and distance | These gentle giants also have gentle speeds of around 2mph. |
| Habitat | Open ocean |
| Diet | Despite their large size and many teeth, the basking shark has a simple diet of plankton. |
| Age lifespan | The average age for a basking shark is 50 years old - although some scientists believe it could be up to 100 years old. |
