They will stick to any hard surface they can find. They stick to rocks, shells, boats, mussels, and dock pillings. Barnacles can be as big as a quater or as small as the tip on a pen. Barnacles have shell like covering which makes them look a lot like mollusks, but actually they are crustaceans. Crustaceans are related to shrimp and lobsters.
Dentists use the cement that barnacles use to attach themselves to boats or other hard surfaces.
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