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Green sea urchin

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This small, round sea urchin is (unsurprisingly!) green in colour and can be found on rocky shores around the UK.

Enw gwyddonol

Psammechinus miliaris

Pryd i'w gweld

January to December

Top facts

Stats

Diameter: Up to 5cm Average Lifespan: 10 years
Common

Habitats

Ynghylch

The green sea urchin is a small spiny urchin that lives amongst the seaweeds on rocky shores and on the seabed down to depths of 100m. It is often found on or under kelp and on seagrass beds. It feeds by grazing on seaweed, sponges and bryozoans and will also eat barnacles, mussels and worms. Their strong short spines are often tipped with a brilliant purple, giving them their other name of purple tipped urchin. Sea urchins are related to starfish and are a type of animal called an echinoderm, which means "spiny skinned." It is sometimes referred to as the shore sea urchin.

What to look for

There are several similar sized sea urchins found in British waters. The green sea urchin is slightly flattened in shape and greenish in colour, with purple tips to the spines.

Where to find

Found on rocky shores all round our coasts, particularly common in the North Sea.

Roeddech chi yn gwybod?

In the past, sea urchins were referred to as sea hedgehogs on account of their spiny shells! They are also sometimes called "burrs" in Scotland, as they look a bit like the spiky little seed pods.