Egg Cockle (also known as the Isocardia Heart Cockle or Strawberry Cockle)
Phylum: Mollusca, Class: Bivalvia, Order: Cardiida, Family: Cardiidae, Genus: Americardia, Species: Americardia media · Cardiidae (Cockle family) · Bivalve (two-shelled), whole shell, heart-shaped when viewed from the side
Species
Americardia media
Shell Type
Bivalve (two-shelled), whole shell, heart-shaped when viewed from the side
Family
Cardiidae (Cockle family)
Size
Approximately 1.25 inches in length, which is average for this species. Adults typically range from 1 to 2 inches.
Color & Pattern
Pale cream to off-white base color with subtle brownish-pink undertones and faint concentric growth lines. The colors appear slightly sun-bleached due to beach tumbling and exposure.
Rarity
Common
Habitat
Found in shallow marine waters, typically living buried just beneath the surface in clean sandy bottoms, often near seagrass beds or coral reefs from the intertidal zone down to moderate depths.
Geographic Range
Western Atlantic Ocean, ranging from North Carolina through the Caribbean, Gulf of Mexico, and down to Brazil.
Description
A sturdy, inflated bivalve shell with a distinctively rounded, egg-like or heart-shaped profile. The exterior features fine, radiating ribs crossed by subtle growth lines, giving it a textured yet smooth feel from wave tumbling. The margins are finely serrated.
Key Features
Inflated, plump profile, rounded egg-like shape, numerous fine radiating ribs, and lack of bright coloration compared to other cockle species.
Collector Value
Low to moderate value. While common and inexpensive, they are popular additions to beginner shell collections and craft projects due to their pleasing symmetry.
Condition Notes
Good condition. The shell is structurally intact with minor chipping along the margin. Surface is slightly worn and sun-bleached from wave action, classified as a 'Good' grade beach find.
Interesting Facts
Cockles are capable of active movement using a muscular, sickle-shaped foot that allows them to leap or dig rapidly back into the sand if exposed.
Ecological Role
As filter feeders, cockles play an important role in maintaining water clarity by consuming suspended phytoplankton and organic particles. They serve as a vital food source for bottom-feeding fish, rays, and sea birds.
Similar Species
Pillbox Lucine (Phacoides pectinatus) or other Atlantic cockle species like Trachycardium egmontianum, which feature much rougher, spiny ribs.
Beach Finding Tips
Look along sandy tropical and subtropical beaches at low tide, particularly after storms or strong onshore winds that churn up the shallow subtidal zone.