Gavin Naylor (copy)

Sharks are no strangers at South Carolina beaches, but usually pose little threat. File/South Carolina Aquarium/Provided

Brenda Sue Morris walked out on Folly Beach from her home this week looking for shark's teeth. She didn't expect to find them still gnashing.

But two or more sharks as long as 4 feet were thrashing their way down the surf line near the Folly Beach Pier for more than two hours mid-day Monday. Charleston County Parks and Recreation Commission lifeguards and Folly Beach Public Safety officers pulled bathers back to the beach ahead of them.

This wasn't the movies. The sharks were in a frenzy for fish, not limbs.

Sharks are nothing unusual in the warm waters off the beaches in South Carolina. Surfers at Folly say they see them swimming under their boards all the time. Getting people out of the water is a precaution against an accidental nip. In the roiling surf, a feeding shark can mistake movement for prey.

The difference this week was the sharks got a little too close for comfort.

"The coastal waters are quite full of bait fish right now and the sharks are merely targeting the bait fish as a natural reaction," Folly Beach Public Safety Director Andrew Gilreath said. "The sharks were a little closer in the surf (but) it is not a completely strange place for them to be."

The ocean is their house, said Morris, a Folly Beach resident.

"You have to respect that. You don't go swimming when they're rolling along in the surf," she said.

A few people are nipped or worse by sharks each year in the Carolinas. Nearly all strikes are unintentional, with the animal mistaking humans for prey fish. A spate of strikes across the South and North Carolina coasts in 2015 caused some serious injuries and raised concerns, but eventually abated.

A few things to keep in mind: You are statistically more likely to be suffocated by sand than killed by a shark. In 2017, 88 people were struck by sharks worldwide — five of them fatally, according to the University of Florida International Shark Attack File.

There were 10 strikes in South Carolina, none fatal. South Carolina hasn’t had a fatal attack since the 1850s.

In comparison, more than 10 million people — in South Carolina alone — are estimated to have visited the beach in 2017, based on statistics compiled by the S.C. Parks, Recreation and Tourism Department and Myrtle Beach Chamber of Commerce.

"Sharks actively feed along the coast, including the surf zone throughout summer months off of South Carolina," said S.C. Department of Natural Resources wildlife biologist Bryan Frazier, who studies the fish. "The relative risk of being bitten by a shark remains very low."

There are any number of tips to avoid shark bites. The most important one might be to avoid swimming in or near schools of bait fish, according to Frazier and others. You'll see them rippling on the water surface, usually with shorebirds diving at them.

Also, avoid spots where people are fishing and don't assume a dorsal fin is a dolphin.

A Facebook post Morris made on the Folly shark incident drew more than 330 comments, some of them a touch sarcastic: "If you touch the water chances are you’ll get eaten alive" and "There's sharks? In the ocean? Whoda thunkit!"

But she didn't mind.

"Dang, you don't go swimming when there's sharks rolling along in the surf," she said. "It was a really fun adventure. Nobody got hurt, and that's the important thing."

Reach Bo Petersen Reporter at Facebook, @bopete on Twitter or 1-843-937-5744.

Science and environment reporter. Author of Washing Our Hands in the Clouds.