The most common explanation is that great whites don’t see well. It has been thought that they mistake people for the seals or sea lions which make up a large part of their diet. There is reason to doubt this, however. Recent information shows that great whites can actually see very well. Also, when attacking seals, great whites shoot up to the surface and bite with great force. When approaching humans, however, they most often move in slowly and bite less hard. They soon discover that humans are not a high-fat meal. “They spit us out because we’re too bony,” says Aidan Martin, director of ReefQuest Center for Shark Research.