Dr. David Kimbro and Dr. Randall Hughes study fear on the oyster reef. How do smaller predator like mud crabs scare oysters into not eating, possibly keeping them from reaching market size and filtering water? How do the mud crabs themselves become scared enough to stop eating oysters? In the ocean, fear is typically transmitted through chemical cues. A predator gives off a chemical "scent," and its prey changes its behavior to avoid being detected. Now Randall and David are looking at an entirely new idea. Do mud crabs hear their predators? And does this make them as afraid or more than chemical cues?