Scuba diver close to a big sea urchin genus Diadema, at Laje de Santos marine state park, shore of São Paulo state, Brazil

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Sea urchins or urchins, sometimes called sea hedgehogs, are small, spiny, globular animals which, with their close kin, such as sand dollars, constitute the class Echinoidea of the echinoderm phylum. There are c. 950 species of echinoids inhabiting all oceans from the intertidal to 5000 meters deep. Their shell, or "test", is round and spiny, typically from 3 to 10 cm ( to in) across. Common colors include black and dull shades of green, olive, brown, purple, blue, and red. They move slowly, feeding mostly on algae. Sea otters, wolf eels, triggerfish, and other predators feed on them. Their roe is a delicacy in many cuisines. The name "urchin" is an old name for the round spiny hedgehogs that sea urchins resemble.

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Size: 6144px × 4068px
Location: Laje de Santos, Sao Paulo, Brazil
Photo credit: © Leo Francini / Alamy / Afripics
License: Licensed
Model Released: No

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