Shark Eye (also known as Northern Moon Snail)
Phylum: Mollusca, Class: Gastropoda, Order: Littorinimorpha, Family: Naticidae, Genus: Neverita, Species: Neverita duplicata · Naticidae (Moon Snail family) · Gastropod (snail/univalve), whole shell, spiral shape with a low spire
Species
Neverita duplicata (formerly Polinices duplicatus)
Shell Type
Gastropod (snail/univalve), whole shell, spiral shape with a low spire
Family
Naticidae (Moon Snail family)
Size
Approximately 1.5 to 2 inches in diameter, which is medium for this species. Adult Shark Eyes typically range from 1 to 3 inches.
Color & Pattern
Smooth, glossy surface with a warm tan to grayish-brown base color. The apical area and suture feature a distinct dark brown or purplish-brown band. The interior aperture is a rich chestnut brown with a characteristic glossy finish. Colors are natural and well-preserved.
Rarity
Common, frequently found beachcombing along sandy Atlantic shores.
Habitat
Found in shallow subtidal and intertidal zones down to moderate depths. They prefer sandy or muddy bottoms where they can burrow just beneath the surface to hunt for bivalves. This is a marine species.
Geographic Range
Western Atlantic Ocean, ranging from Massachusetts down to Florida and the Gulf of Mexico, as well as the coast of Brazil. The specimen matches the fauna of the Outer Banks, North Carolina.
Description
A classic, sturdy moon snail shell featuring a globose, rounded body whorl and a very low, flat spire. The surface is exceptionally smooth and polished with fine growth lines. The most striking feature is the heavy, glossy brown callus that completely covers or obscures the umbilicus, giving it a solid, button-like appearance in the center.
Key Features
Globose shape, very low spire, smooth polished exterior, rich brown coloration around the apex, and most importantly, the thick, glossy brown umbilical callus that fills the central cavity.
Collector Value
Low to moderate value. While very popular among casual beachcombers and shell crafters due to their appealing shape and glossy finish, they are too common for high commercial value. Typically sold as a common souvenir or collected personally.
Condition Notes
Good to Fine condition. The shell is fully intact with a smooth surface and minimal wear. The original coloration and glossy finish are well-maintained, with no major chips or structural damage.
Interesting Facts
Shark Eyes are predatory carnivores that drill smooth, countersunk circular holes into the shells of other bivalves (like clams) using a combination of acidic secretions and their radula to access the soft tissue inside. The prominent dark callus on the shell led to the common name 'Shark Eye', as it resembles the eye of a shark.
Ecological Role
Acting as apex predators among benthic mollusks, Shark Eyes help control populations of clams and other bivalves. Their drilled shells are frequently repurposed by hermit crabs as mobile homes after the original owner has finished with them.
Similar Species
Neverita lewisii (Lewis's Moon Snail) which is much larger and paler, and Euspira heros (Northern Moon Snail) which lacks the dark brown callus and has an open umbilicus.
Beach Finding Tips
Look along high-energy sandy beaches especially after storms or during low tide. They are often found half-buried in the wet sand or rolling in the surf line. The Outer Banks in North Carolina is an exceptional location for finding them.
Notes
Outer banks, North Carolina on Kill Devils Hill beach