Super-spiny sea creatures
Live sea urchin
- Sea urchins come from the same family as starfish. They live on the sea floor, often buried in sediment.
- They are usually round, and about the size of an apple.
- Sea urchins have sharp spines to protect themselves from predators. Sometimes the spines contain poison.
- The sea urchin’s spines fall off after death, so most fossils consist of the test (shell) or scattered spines.
- Look closely at sea urchin fossils and you can see the knobbles where the spines were attached to the test.
- You can also see rows of tiny holes are where flexible ‘tubed feet’ extended through the shell. Each had a sucker on the end which stuck to the sea bed. The tube contracted to drag the animal along.
- The delicate shell is often crushed, but some like this are beautifully preserved.
- Take a closer look at this perfect sea urchin at Dorset County Museum.
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