WTF Fun Fact – Green Sea Urchin Helmets

Green sea urchin (Strongylocentrotus droebachiensis) are often found covering themselves with the shells of hermit crabs, rocks, and other debris. Scientists don’t fully understand why they do so. – WTF Fun Facts

Source: Multiple factors explain the covering behaviour in the green sea urchin, Strongylocentrotus droebachiensis – ScienceDirect