These corals get their common name from the grooves and channels on their surfaces that look like the folds of the human brain. There's more than one kind of "brain coral"—several species from two different families of corals share the name—but all help build coral reefs.
Coral reefs around the world are in danger. Silt (fine soil) smothers coral when it washes off the land from farm fields, roads and building sites. More towns and resorts near shore mean more sewage, oil and chemicals in the water.
While staghorn corals grow rapidly to gain new territory, slow-growing brain corals rely on brawn. They hold their ground by being solid and strong enough to withstand the storms that pound more delicate corals to rubble.