July 7, 2008: Sea Urchins

Tideflat Critters

Sea urchins are echinoderms, and are related to sea cucumbers and sea stars. They're covered in protective spines, use tube feet for locomotion, and normally feed on algae. Sea urchin gonads, known more appetizingly as uni, are a popular food in Japan.
The little urchin above lived up to its name by stabbing Oyster Fan underneath her thumbnail, leaving a shard of its spine lodged in her cuticle. Cute.
Technically, this urchin is a Stronglyocentrotus droebachiensis. But if that was too much gobbly-gook for you, just call it a green urchin.
Below: a close up photo of a sea urchin test (or shell), courtesy of Wikipedia. In live animals, spines attach to the raised bumps via a ball-and-socket joint, and gills and tube feet pass through the holes.


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