Moon Snail (Shark's Eye or Atlantic Moon Snail)
Phylum: Mollusca, Class: Gastropoda, Order: Littorinimorpha, Family: Naticidae, Genus: Neverita, Species: Neverita duplicata · Naticidae (Moon Snail family) · Gastropod univalve, whole shell with spiral/globular shape
Species
Neverita duplicata
Shell Type
Gastropod univalve, whole shell with spiral/globular shape
Family
Naticidae (Moon Snail family)
Size
Approximately 2 to 3 inches in diameter, which is average for an adult specimen of this species. Adults typically range from 1.5 to 3.5 inches.
Color & Pattern
The exterior exhibits a smooth, polished surface with a muted brownish-grey to tan base coloration, showing subtle concentric growth lines and a prominent darker brown or chestnut-colored apex. The colors appear slightly sun-bleached but mostly natural.
Rarity
Common, frequently found washed ashore on sandy beaches along its native range.
Habitat
Found primarily in shallow subtidal and intertidal zones down to moderate depths. They prefer sandy or muddy substrates where they can easily burrow beneath the surface to hunt.
Geographic Range
Western Atlantic Ocean, ranging from Massachusetts south through the Gulf of Mexico and along the coast of South America.
Description
A classic globular, low-spired gastropod shell with a smooth, porcelain-like texture. The body whorl is large and dominates the shell structure, curving smoothly toward a concealed or heavily calloused umbilicus. The spiral apex is tight and distinctively colored in richer brown tones, contrasting with the paler body.
Key Features
Globular shape, low spire, smooth polished exterior surface, large body whorl, and a characteristic thick callus that partially or fully covers the umbilicus depending on the exact species variant.
Collector Value
Low to moderate value. While very popular among casual beachcombers and beginner shell collectors, they are too common to command high prices among advanced collectors, typically selling for a nominal amount in souvenir shops.
Condition Notes
Good condition. The shell is intact with minor surface wear and slight bleaching from sun exposure, but retains its structural integrity and primary coloration. Collectibility grade is Good.
Interesting Facts
Moon snails are formidable carnivorous predators. They drill precise, bevel-edged holes into the shells of bivalves using an acidic secretion and their radula, then feed on the soft tissue inside. Their egg masses, known as 'sand collars,' are made of sand glued together with mucus.
Ecological Role
Acts as a key apex predator in benthic soft-bottom communities, helping to regulate bivalve populations and maintain marine ecosystem balance. They are preyed upon by various fish, sea birds, and larger marine predators.
Similar Species
Neverita lewisiana (Lewis's Moon Snail) and Euspira heros (Northern Moon Snail). They can be distinguished by differences in size, umbilical callus thickness, and geographic distribution.
Beach Finding Tips
Look along sandy beaches shortly after low tide or following a strong storm. Keep an eye out for the smooth, rounded shapes rolling in the surf or half-buried in wet sand.