It is not exotic. The humble, hard-shelled bivalve of the estuary. The cockle has a thick, heavy shell with strong, radiating ribs that give it a distinctive, corrugated appearance. The colour varies from white to grey to pale brown, often with darker bands or patches. The inside of the shell is clean and white, with a deep purple muscle scar that marks where the animal anchors itself shut. These animals are the filter-feeders of the sand and mud. They live just below the surface, with only their two short siphons sticking up into the water. One siphon draws water in, pulling plankton and algae towards the cockle's gills. The other squirts clean water back out, a tiny fountain that you can see if you stand still in the shallows at low tide. Their shells are strong enough to resist the crushing beaks of hungry oystercatchers and the pressure of your foot when you accidentally step on one. Cockles are the classic Kiwi beach forage. You dig them up with your hands or a small rake, rinsing them in the sea to wash away the sand. Back home, you steam them open in a pot with white wine, garlic and butter. The meat is sweet, salty and briny, the taste of a summer afternoon at the beach. Some people eat them raw, straight from the shell, claiming that is the only way to taste the true estuary. To eat a cockle is to eat the memory of the estuary. A ribbed, hard-shelled, delicious bivalve that you collected yourself, with sand between your toes and the sun on your back. The tuangi is a traditional food source for coastal tribes, collected from sand flats at low tide, eaten raw or cooked in a hāngī. The shells were used for tools and jewellery. Today, it remains the shellfish of the Kiwi summer, collected by families on the beach, steamed open and eaten with buttered bread. Local populations affected by overharvesting, pollution and sedimentation. A popular recreational shellfish, collected by thousands of Kiwis every summer. Most common in northern New Zealand where waters are warmer.