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Color: While typically dark, their spines can vary from white to orange, with some having orange tips or being entirely white.
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Test: The test is usually dark, especially in interradial regions, which are the areas between the spines.
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Spines: They possess long, obvious spines, and their spines are often inclined towards adjacent ambulacra, giving the appearance of a pentaradiate cross.
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Podia: These urchins have long and obvious tube feet (podia) that help them move and collect debris.
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Diet: Tripneustes gratilla is herbivorous, feeding primarily on algae.
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Habitat: They are found in a variety of tropical habitats, including coral reefs, seagrass meadows, and algal forests.
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Covering Behavior: They are known for their "covering behavior," using tube feet to cover their aboral (top) surface with debris like rocks and other materials.
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Predators: Common predators include pufferfishes, octopuses, and humans.
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Venom: They possess venom but it doesn't typically cause severe stings.
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Edibility: While they are not the most commonly consumed sea urchin, some cultures do eat their gonads.
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Other names: They are also known as cake, Parson's hat, Halloween, Hawaiian, priest-hut, pincushion, and hairy sea urchins