Shelly Negrotti / Associated Press
Walter Szulc Jr., in the kayak at left, looks back at the dorsal fin of an approaching shark at Nauset Beach in Massachusetts' Cape Cod. No injuries were reported in the incident July 7, but beach-goers -- not to mention the kayaker -- admitted to being unnerved. More:
Beach-goers scream 'Shark!' SEE MORE GALLERIES
Cousteau Society / Getty Images
A great white shark makes a distinctive outline above a diver. The species' physical appearance, bite pattern and tooth marks make it readily identifiable in recorded unprovoked attacks on humans, according to the report "Responding to the Risk of White Shark Attacks." When asked about the difference between white sharks and great white sharks, Chris Lowe, director of the Cal State Long Beach Shark Lab, said they were the "same critter." "This is the problem with common names," he said. "Most scientists just call them white sharks. Besides, we don't want them to get too cocky thinking they're 'greater' than all the other species." Related:
More sharks, more people, more dangerous run-ins SEE MORE GALLERIES
A photo of a shark seemingly stalking a kayaker off Cape Cod went viral, in no small part because the shark's so close it appears photoshopped. Here's a look at other shark photos that made our hair stand on end.