A cockle is a type of bivalve mollusk found in marine and estuarine environments. They have a rounded, heart-shaped shell with distinct ridges and are often found buried in sandy or muddy substrates. Cockles are popular in various cuisines around the world and are harvested for food. These creatures play an important role in their ecosystems, serving as a food source for various predators, including birds and fish. Cockles are also filter feeders, helping to maintain water quality by filtering out plankton and other particles from the water, contributing to the health of their habitats.