If you feel something other than sand under your foot while you're in the ocean -- and it doesn't send a stinging barb into your ankle or pinch your toe -- it's probably a sand dollar.
Most people know of sand dollars in their deceased state -- a bleached white skeleton. They are often turned into Christmas ornaments, as filling for glass lamps and even earrings. Some even ascribe religious meaning to the sand dollar's various details.
But few beachgoers realize these pretty white shells were once living creatures, also known as keyhole urchins, and that it's illegal to remove them from the beach when they're alive. The fine is $500 for taking live sea creatures from South Carolina beaches, says Bob Bender, curator for the Lowcountry Estuarium in Port Royal.
Bender says a lot of visitors are surprised when they take buckets of sand dollars home, open the trunk and are hit with an overwhelming odor.
"A lot of people don't know they're a live creature," he said.
Lowcountry beaches are home to an abundance of the disk-shaped echinoderms that move along the ocean floor with tiny bristle-like tube feet, sucking up organic matter as they go. The five pieces that come out when you crack them open -- which some believe symbolize peace doves -- are actually mouth parts.
Carlos Chacon, executive director of the Coastal Discovery Museum on Hilton Head Island, says he sometimes sees beachgoers remove sand dollars or sees piles of ones left in the sand that were once alive.
"We don't want people to pull them out of the water," he said. "Lots of people do because they don't know any better."
They might also think that since there are so many, taking a few won't make a difference, but Chacon says that with hundreds of thousands of beach visitors each year, those "few" can turn into big numbers.
"If they're brown and if their feet are moving, then they're alive," Chacon says, "put them back on the beach, or even better, put them back in the water."
But if they're dead, then they're fair game for beachgoers to remove. After they've been in the sun they turn to the chalky white appearance that attracts so many beachcombers and beach-store shoppers.
Bender, the estuarium curator, recommends that you not put sand dollars in bleach to speed the whitening process but instead leave them out in the sun and rain for a couple weeks.
Bender says the best time to find dead sand dollars is after nor'easters and in the winter when there are fewer shell hunters. Going out at mid-tide when the tide is receding will yield the best results.
As to the sand dollar's importance: "They're part of the food web," says Bender.
And after they're dead, they bring much pleasure to many a beachcomber and beach-shop owner.