The cárdidos or cardíidos (Cardiidae) are a family of bivalve molluscs. Several species of the family are commonly known as cockles, especially the edible European species (Cerastoderma edule). Their shells are common on many beaches in the world. The leaflets are distinguished by their symmetry, heart-shaped, and strong and pronounced longitudinal ribs. Cockles live buried in nearshore areas. The family also includes much larger species, such as giant clams.