The Great White shark is on the prowl. In the chilly northern California waters above its massive, streamlined head, near the surface of the Pacific by North Salmon Creek in Sonoma County, the toothy leviathan spots a gliding form. It seems to be that of a sea lion or seal, the Great White’s favored prey along this stretch of rocky coast. But the shark is uncertain about what it’s glimpsed. Great Whites are color blind, it’s thought, and the waters in which they choose to hunt are often murky, all the better to conceal their lurking presence. The shark’s only way to determine the identity of the tantalizing silhouette is to use its most trustworthy sense organ, its mouth.  And so, like a blind person tapping with a cane, the shark closes in on the moving mystery object and gently — in Great White shark terms — nips its side. The result is confusing. This doesn’t taste like seal flesh. It doesn’t taste like flesh at all. The shark, a remarkably prudent creature despite its reputation …