Why sharks attack — and why they don’t. In Florida, the waters are complicated

Patrick Farrell/Miami Herald file

A shark bit a human in the Florida Keys again.

Last weekend, the family of a 10-year-old said the boy lost part of his leg in the attack. This was at least the fifth shark attack off Monroe County this summer.

“He is doing quite well,” said Jason Rafter, a spokesman for the Florida Fish and Wildlife Conservation Commission on Tuesday. “There is a lot of positive energy coming from the youngster.”

So, why do sharks attack? Do they crave human flesh? Or do they think they’re going for a big fish?

It can get complicated.

For starters, sharks use their teeth to feel objects around them and to check for possible food.

“That’s a part of their arsenal of sensory structures, the way they sense the world,” Neil Hammerschlag, director of the Shark Research and Conservation Program at the University of Miami. “It might just be a case of curiosity.”

People are far more dangerous to sharks than the other way around, according to the Florida Fish and Wildlife Conservation Commission. The FWC, which enforces laws in state waters, says an increase in people using the water causes more bites.

A bull shark is thought to have attacked the boy off the Keys over the weekend, when the North Carolina family was visiting the Keys. The species is considered more aggressive than others, and not as picky an eater.

But most sharks usually don’t want a human meal and shark bites remain few and far between, especially in the Keys.

“They’re extremely rare,” said Hammerschlag, “If sharks wanted to bite people, there’s nothing easier than to munch on people all day if they wanted to. Sharks generally avoid people,” he said.

Most shark bites are what Hammerschlag and other shark insiders call “bite and release,” meaning a shark isn’t repeatedly attacking a person after one bite.

Florida is home to various species of sharks that range from a few feet to more than 40 feet long and, “none see humans as a food source,” FWC says.

More than 13 species of shark are in nearshore waters, which they use as nurseries.

“Experts believe that most shark attacks are cases of mistaken identity, which explains why nearly all shark attacks that occur in Florida waters are of a bite-and-release nature,” the FWC says.