Millions of television viewers watching the surfing championships in South Africa witnessed a spectacle that seemed straight out of a horror film. While sitting on his surfboard, waiting to compete, surfer Nick Fanning was seemingly attacked by a great white shark on live television. Or was he? In plain sight, viewers saw the shark slowly emerge from the water and gnaw at his surfboard. Fanning naturally started flailing in the water to get away from the shark, but as rescuers rushed to the scene, the shark simply swam away. Further review of the footage suggests that perhaps the shark was not aggressive at all, and more likely just curious. Scientists now think that sharks use their teeth similarly to the way humans use their fingers or cats use their paws to poke or prod an unknown object. What is unclear to researchers is the nature of most shark encounters. Are the sharks being aggressive or just curious? Data shows that when a shark bites a human, it is more likely to swim away than continue the attack. Most shark "attacks"do not end in a fatality. Still, sharks are ferocious creatures and can be deadly. The most aggressive sharks are bull sharks and mako sharks, although attacks are incredibly rare. These sharks are thought to be aggressive because humans are roughly the same size as seals, one of their main prey in the water. Other sharks, such as the hammerhead shark or nurse shark, usually only attack when provoked. Still, other sharks, like the whale shark, a gentle giant, are no threat to humans.