Clua has conducted several autopsies on shark attack victims, and is usually able to identify the shark based on tooth marks. He recently, for example, determined that a 19-year-old surfer from New Caledonia died as a result of a white shark attack. The findings are published in the Journal of Forensic and Legal Medicine.
Most studies conclude that hunger is not the main motivation of white shark attacks but, in this case, Clua and colleague Dennis Reid determined that "the several strikes and the heavy loss of flesh during this attack support the hypothesis of a feeding behavior."
The researchers believe that the shark was a juvenile "still in a learning phase as a top predator." Since white shark learning can occur as a result of trial and error experience, a young shark could learn to identify humans as prey.
Burgess said that "it's highly unusual for an individual shark or other animal to repeatedly prey upon humans, but it can happen."
It doesn't happen very often, though. Burgess and others are quick to point out that a person's odds of getting killed by a shark are 1 in 3.7 million. To put that into perspective, the chances of being killed by another human, based on data from the UN Office on Drugs and Crime, are roughly 1 in 16,000.