What Divers Should Know About Brain Coral

When exploring the vibrant coral reefs, you'll often encounter the distinctive formations known as brain corals. Their common name comes from their generally spheroid shape and grooved surface, which strikingly resembles a human brain. These significant stony corals are vital builders of the reef structure, formed by colonies of genetically identical polyps that secrete hard calcium carbonate skeletons. Divers typically find them in shallow, warm water coral reefs across all the world's oceans.

These robust structures are truly impressive. Some of the largest brain coral colonies can reach over 1.8 meters (6 feet) in height and boast lifespans of up to 900 years, making them ancient inhabitants of the reef. While their hard surface provides excellent protection against physical damage and predators during the day, they exhibit different behavior after dusk. At night, brain corals extend their tiny tentacles to capture small drifting animals for food. For the more observant diver, it's worth noting that some genera, such as Favia, can be semi-aggressive, using extended sweeper tentacles to sting competing corals in their vicinity during the dark hours.