When you see coral, you may notice its plant-like shape and often stony exterior. Is coral a plant? Or is it a rocky animal? Believe it or not, what we know as “coral” is actually a collection of hundreds or thousands of animals called polyps. They are cylinder shaped, and their bodies secrete a substance called calcium carbonate, which forms a hard skeleton of limestone that attaches to rock or the dead skeletons of other polyps.
You may have thought corals were plants since they don’t move around the ocean floor! But they ARE animals animals that take root in a specific location. Plants have roots, so why aren’t corals plants? Because they don’t make their own food the way plants do! What do corals eat? They use their tentacles to capture tiny animals, but they are also nourished by tiny algae that live within the coral tissue!