Inside the crevice, the burrowing sea urchin uses its spines to dig the rocky substrate where it lives. It excavates some limestone, while feeding on encrusting algae. As a result, it produces a deep and long crevice that provides a big enough house for itself. Often, this provides wider space for other animals to live, such as small shrimps, tiny crabs, etc.

The sea urchin (Echinometra mathaei) is hiding in a crevice. This burrower provides more space for other species like crustaceans, mollusks,   etc
The sea urchin (Echinometra mathaei) is hiding in a crevice. This burrower provides more space for other species like crustaceans, mollusks, etc. It is found on reef ecosystem in Triton Bay, Kaimana, West Papua and other reefs in the Indo-Pacific region. It uses its spine to dig rocky substrate where it lives.
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