Sea urchin

Fossil Favourite Stamp Sea urchin

Super-spiny sea creatures

Sea urchin
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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