Writing and beach item photography by Judy Drew Fairchild
Walking along a Lowcountry beach is an exercise in beauty – sun glinting off the water; the ebb and flow of waves on the shore; pelicans gliding just above the ocean’s surface. But if you look a little closer (and down!), you will find shells and other signs of the many animals that live, hunt, burrow and reproduce in this remarkable shoreline ecosystem. Most animals that call this environment home can be divided into a few basic categories. See how many you can find on your next walk!
A large variety of snails can be found on Lowcountry beaches. Snails are univalves, which means they are one-shelled mollusks. For the most part, these are carnivorous animals that have a strong foot used to propel them through the sand. Sometimes you can find trails that lead to a live snail under the surface of the sand! Most snails have an operculum, which helps to seal the shell opening and protect the animal from predators.
Lettered olive snail shells became the state shell of South Carolina in 1984 and were given their name because the markings on them can resemble calligraphy letters. They are predatory sea snails that use their long foot to grab prey, such as coquina clams and mole crabs. Lettered olive snails live under the sand in shallow water and can grow to be 2.5 inches long. They live completely outside of their shell and do not have an operculum to close off the shell opening.
Moon snails plow through the soft sands of the swash zone. The front part of the foot is used for digging, and the mantle surrounds the shell to streamline its shape and allow the snail to move through the sand below the surface. These mollusks have a radula, a sort of toothy-tongue apparatus, which can be used to bore a hole into the shell of its prey. When you see shells on the beach with perfect holes in them, they were probably moon snail meals!
Some of the largest snails that live on Lowcountry beaches are whelks. When alive, these animals can be found just at or below the surface of the sand in tide pools. They also cruise the inter-tidal zone and shallow water looking for food. Whelks are predatory snails that uses the sharp
side of their shells to pry apart bivalves, such as clams and oysters, and scrape out the meat with a tongue-like radula.
Channeled whelk shells have a smoother exterior than knobbed whelks, and they have hard edges in the channels of the shell. They are also wider, rounder and lack the large protruding knobs found on the knobbed whelk shell.
Both knobbed whelks and lightning whelks have knobby shells, but they open in different directions if you are looking at the hole. Knobbed whelks open on the right and lightning whelks open to the left. Knobbed whelks are more numerous in the Lowcountry.
Mollusks with two-sided shells are bivalves. The shells are most commonly found as single halves along the beaches, although occasionally you can find them with both sides still attached – and sometimes still alive!
Perhaps the smallest and most colorful bivalve is the coquina clam, which is often found in the wash zone of the wave. These tiny animals are a great source of food for moon snails, shorebirds and ghost crabs, and their presence is an indicator of a healthy beach. Occasionally a large group of them will become stranded in a tide pool, which creates a natural work of art.
On the other side of the size spectrum for bivalves on South Carolina beaches are Atlantic cockles, which can grow up to 4.5 inches long. Living cockles are often found at the edge of tide pools with their hinges pointed downward, which allows their foot to anchor them into the sand. Cockles are filter feeders, drawing water in to get nutrients, then puffing it out.