Shark Eye

The shark eye, Neverita duplicata, is a moon snail with a smooth, rounded shell and a low spire. Darker early whorls surrounded by paler shell can create an eye-like appearance. The broad final whorl and semicircular opening are useful clues, but a shell viewed only from above may hide features needed to separate similar moon snails.

Atlantic Florida context

Florida DEP’s 2014 St. Lucie Inlet Preserve animal inventory lists the shark eye under the older name Polinices duplicatus. That is a dated local occurrence record within the regional coastline, not a claim that living animals are abundant there now. Its natural setting is sand and other suitable shallow-bottom habitat, rather than an animal perched conspicuously on coral.

A washed-up shell may be far easier to find than its living maker. Record whether an encounter involves a live snail, an empty shell or a hermit crab using the shell. Those observations are biologically different and should not be combined into a single unquestioned sighting.

Feeding and movement

A large muscular foot helps the snail move through sediment and handle prey. Shark eyes can attack smaller shelled mollusks by boring a hole and feeding through it. A neat hole in an empty clam shell is evidence of a predatory interaction, but it does not by itself identify which individual or species made it.

Avoid describing every moon snail as having an identical, exclusive diet. Studies of feeding and isotope evidence have added complexity to older accounts, and similar-looking species have also been confused. This guide emphasizes well-supported shell-boring behavior without claiming that it describes every meal.

Sand collars

The egg structure is a flexible collar made from mucus, sand and eggs. It can look like an artificial fragment until its regular curved shape is recognized. A Florida photographic record documents such a collar at Vilano Beach; that northeastern locality supports the reproductive example, not a separate claim about a Palm Beach spawning season.

Leave collars undisturbed rather than testing their strength. Photograph their position and shape without removing them from the habitat.

Compare carefully

The false shark eye, Neverita delessertiana, is an important lookalike. Spire form and the underside around the umbilicus need attention; a casual color match is insufficient. Use a reliable shell reference and accept a tentative moon-snail identification when the necessary features are concealed.

Current live-shell and protected-area rules apply independently of identification. Do not excavate animals or collect egg collars merely to complete a photograph.

References

• National Shell Museum: Shark-eye shell characters
• National Shell Museum: False shark-eye comparison
• Florida DEP: Dated St. Lucie Inlet Preserve inventory
• UF/IFAS: Moon-snail feeding and sand collars
• Photographic record of a shark-eye egg collar
• FWC: Live-shell collection guidance

Collection and seafood safety

Identification is not permission to collect. FWC distinguishes empty shells from shells containing living animals; a recreational saltwater fishing license is generally required for live-shell harvest. Species rules and park or sanctuary restrictions must also be checked. Leave animals undisturbed while identifying them. Current FWC guidance. Guidance reviewed November 12, 2026. No location-specific harvest or sanitation clearance is given.

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