Are corals plants or animals?
Corals look like plants, but they are actually animals that use their tentacles to catch tiny sea creatures to eat. They usually live together in large groups, called colonies. Over thousands of years the skeletons of dead corals build up on top of one another to form a coral reef. Corals are related to sea anemones and jellies. The individual coral animal, called a coral polyp, has a soft body topped by a ring of stinging tentacles for catching food. Some kinds of coral polyps secrete a hard underlying skeleton made of limestone. Coral polyps often retreat into cuplike depressions in the skeleton for protection. It builds the skeleton by combining carbon dioxide (CO2) and calcium (Ca) in the water to make calcium carbonate (CaCO3), also known as limestone. When corals die, other corals build on top until a great reef is formed.
