North Carolina's Mollusks & Seashells

I wasn't a normal kid. While my boyhood friends put together model cars and played with Hot Wheels, I collected seashells and studied mollusks. Oh, I built tree houses and splashed in the creek like other country boys, but something about those seashells captured my young imagination and it hasn't let go yet.

At one time or another, seashells captivate most people. Usually, it happens during a stroll along the beach, when the sights, sounds, and smells of the seashore conspire to infuse an awareness and appreciation of the natural world at our feet. We pick up shell after shell and marvel at their artistry and architecture. Such treasures, we muse, must be possessed. We must take them home and let them continuously enrich us with their exquisiteness. Then, once back home, we toss them in a box and stuff it in the attic.

What a sad interment for one of nature's most fascinating and stunningly beautiful animals. Perhaps if we learned a little more about the creatures that live in seashells, our appreciation for them might linger awhile after we leave the beach. Seashells are the calcium carbonate homes for a large and diverse group of invertebrates called mollusks, which includes the familiar snails and clams, as well animals like the squid and octopus. The body of a typical mollusk is composed of a fleshy, visceral mass that contains the digestive, excretory, and reproductive organs, and a fleshy mantle that secretes the calcareous shell. Depending on the class, a mollusk may also have a well-developed head (complete with eyes and mouth) and a foot that is used for getting around (squid and octopus tentacles are highly modified feet). Scientists generally recognize seven different classes of mollusks, consisting of some 130,000 species. This easily makes the mollusks the second-largest group of animals in the world, behind the insects. Also, only the insects surpass them in color variety. And no animal group on earth can compete with the mollusks in form, texture, and pattern.

While the greatest variety of mollusks occur in tropical regions, North Carolina's beaches, sounds, and offshore waters support a surprising diversity—some 1,000 species. At Cape Hatteras, the cool Labrador Current from the north meets the warm Gulf Stream from the south, resulting in our state being the northern limit for certain warm-water species such as the Scotch bonnet—North Carolina's official State Seashell—and the southern limit for cool-water mollusks such as the blue mussel. In addition, the diversity of habitats—salt marshes, mud flats, sand beaches, sounds-contributes to the complexity of species. Even species that require rocky environments can find a home on North Carolina's man-made jetties and other near-shore underwater structures, as well within the many shipwrecks off the coast.

Of the world's seven classes of mollusks, five occur in North Carolina. Class Gastropoda (univalves) is the largest group. Most gastropods have a single, coiled or cap-shaped shell, but the shell is absent in a few species. Familiar species like the whelks, conchs, and the terrestrial land snails belong to this class. The common garden slug is a gastropod without a shell.


Hinged, two-part shells easily distinguish mollusks of the class Bivalvia (bivalves). Bivalves are the second-largest group of mollusks and include the well-known oysters, clams, and mussels. Class Polyplacophora (chitons) consists of strange little creatures that have eight shelly plates encircled by a leathery girdle. They spend their lives attached to rocks or other shells. Beachcombers rarely find either of the two chiton species recorded from North Carolina.

Members of the class Scaphopoda (tusk shells) live in shells that resemble the ivory tusks of large mammals-just on a much smaller scale. Some two-dozen species of tusk shells live off the North Carolina coast, and although they often wash up on the shore, the shells are so small that most beachcombers don't recognize them.

Members of the final class of North Carolina mollusks are among the most highly developed invertebrates in the world. Class Cephalopoda consists of the squids, octopuses, and cuttlefish, and includes the well-known chambered nautilus of Pacific waters. The octopus has no shell, while the squid has a small, loosely coiled shell that grows inside the animal. These "ram's horns" occasionally wash up on North Carolina beaches.

Mollusks are among the most diverse and widespread groups of animals in the world, a fact that is largely responsible for their many uses, both traditional and modern. Early civilizations ate mollusks and used them for making dyes. They also used their shells for utensils, ornaments, and religious ceremonies and even used shells for currency.

Our own Native Americans cut and polished shells and used them for necklaces or woven belts called wampum, which they used for trading. Most valued was wampum made from the deep-purple shells of the northern quahog, North Carolina's most popular edible clam. Even the early colonists used wampum as a form of currency during the 17th century.

Modern uses for mollusks and their shells are even more extensive: We collect them, eat them, wear them as jewelry, hunt them for sport, build roads with them, make lampshades out of them, flick our cigarette ashes in them, decorate our houses with them, name our companies after them, use them for corporate logos, develop medicines from them, use them in religious rituals, grind them up and spread them on our lawns, photograph them, and plant flowers in them. And, we just simply admire them.

Several of North Carolina's mollusk species are harvested commercially for food. By far the most popular is the venerable eastern oyster. The heyday of North Carolina oyster fishery occurred during the late 1800s and early 1900s, with 1.8 million bushes harvested in 1902 alone.

Since then, harvests have gradually declined because of pollution, disease, over-harvesting, and damaging collection methods. In 2001, less than 50,000 bushes were commercially harvested. Today, various organizations are working hard to reestablish the prominence of North Carolina's oyster fishery.


Other commercially harvested mollusks include northern quahogs (known locally as hard clams) and scallops. Several additional North Carolina mollusk species are collected for personal consumption. Coquina clams-those little, variably colored, clams you often find on the beach-make a tasty broth, and whelk meat makes great chowder.

Despite the utilitarian roles we often assign to seashells, our wonder at their complex artistry never ceases. You can't help but marvel at how that slimy blob creates a design that is so precise, so beautiful, so utterly fascinating. Perhaps the philosopher and mathematician René Descartes pondered this in 1638 when he discovered the mathematical formula for the curves of univalves and shells like the chambered nautilus. The assignment of this formula—known by mathematicians as the equiangular (or logarithmic) spiral—in no way diminishes the layman's sense of awe. And just how is it that we hear the ocean when we hold a shell to our ear? Well, that one's easy. We're just hearing ambient noise within the shell's resonant cavity. You can simulate the effect by simply cupping your hands to your ear. So, no molluscan mystery there.

Collecting seashells can be a rewarding hobby, but unlike collecting stamps or coins, these are animals and their homes. During the heyday of seashell collecting from the 1950s to the 1970s, collectors gave little thought to fact that mollusks had to be killed to obtain the best specimens. Today, a different attitude prevails and unless you are a research scientist, there is no reason for collecting living mollusks for their shells.

But that shouldn't discourage anyone from taking up shell collecting. You can start with empty shells on the beaches and on the sound-side sand and mud flats at low tide. Consider bringing a camera with you to photograph any living specimens you find. In fact, seashell photography is a wonderful method of "collecting mollusks" without killing them. Collecting seashell photos can be just as rewarding collecting the shells. The best time to search for shells on North Carolina's beaches is in winter and particularly after a storm, when you often find species that don't ordinarily wash up on shore. Some of the best beaches in the state for collecting seashells are within Cape Lookout National Seashore. Since they are accessible only by boat, they don't receive the heavy tourist traffic that other beaches do. Keep in mind that some public beaches have restrictions on the amount of shells you can take. For instance, at Cape Lookout National Seashore you are limited to two gallons of empty shells per day, and no living mollusks may be collected.

Collector Ed Shuller says anyone seriously interested in collecting seashells should get advice and support from other collectors. Shuller should know: He's the president of the North Carolina Shell Club and only began the hobby himself four years ago. The assistance he received from fellow club members was extremely beneficial to him.


To Tell The Truth was a popular TV game show during my youth. On the show, a group of panelists tried to guess which of three contestants-all claiming to be the same person-was telling the truth. Imagine my astonishment when one of the contestants was my childhood hero, malacologist Dr. R. Tucker Abbot. (A malacologist is a person who studies mollusks.) I watched intently, smug in the thought that I would be able to guess easily who the real Dr. Abbot was. Unfortunately, at the age of eleven, I knew much more about seashells than I did about observing human psychology, and consequently I misjudged the contestants miserably.

Today, more than thirty years later, I'm still better at watching coquina clams burrow in the surf or knobbed whelks lay a string of egg cases than I am at observing humans. Who knows, maybe someday I'll even poke around in the attic and try to find that old box of shells.