Life can be tough for one of California's most common and beautiful sharks. Living much of the year on sandy bottoms around bays and coastlines, leopard sharks move temporarily into shallow tidal areas between April and August to mate. Here, dozens at a time may patrol shorelines so shallow that their dorsal fins protrude several inches above the water as they size each other up and pick mates. This behavior, however, makes them extremely vulnerable to the sevengill shark, their fiercest predator. Sevengills have no problem finding and trapping leopard sharks in shallow waters, sometimes chasing them so aggressively that both predator and prey end up flopping on the beach before the sevengill drags its victim back into the water. Perhaps this is the reason leopard sharks retreat into deeper waters immediately after mating.