Swarm of cownose rays descends on Charleston Harbor, photos show. What was going on?

In a rare case of marine life turning the tables on researchers, a large school of cownose rays showed up in Charleston Harbor — and congregated outside the South Carolina Marine Resources Center.

Photos shared by the S.C. Department of Natural Resources show the sea creatures filled (or blocked?) the research center’s boat slip.

“We enjoyed an unusual sight at our Marine Center in Charleston earlier this week — a graceful group of cownose rays,” the state posted on Facebook.

“They attracted a crowd outside the administration building. ... They’re a shy species that tends to avoid humans, so they’re rarely responsible for stings.”

However, they can sting when necessary, using “a keratin barb with a venomous spine,” the South Carolina Aquarium reports.

State shark biologist Bryan Frazier suspects the gathering involved “a bunch of teenagers hanging out,” according to the post.

“In the summer, millions of these rays migrate from Florida to the Chesapeake and Delaware bays, where they mate and give birth. ... That party has already begun, so ... this is likely a group of younger, non-breeding rays that will stay in South Carolina for the summer,” officials wrote.

Cownose rays can grow to 4 feet wide, weigh as much as 70 pounds and have “been seen jumping out of the water,” the aquarium says. Such antics are likely due to disputes over territory, experts say.

Their chief enemies are sharks and cobia, the Florida Museum of Natural History says.

This story was originally published June 17, 2021 at 2:02 PM with the headline "Swarm of cownose rays descends on Charleston Harbor, photos show. What was going on?."