The cockle is a type of clam in the family Cardiidae. It is a bivalve shellfish found on sheltered sandy beaches throughout the world and collected by raking them from the sands at low tide. The cockle has an almost circular shell, heart-shaped when viewed from the end, hence the Latin family name. Most have pronounced radial ribs. They are generally available pickled in jars in brine or vinegar, but when found fresh they can be eaten either raw or steamed for around five minutes and checked in the same way that you would mussels or clams. In stalls in places like Morecambe where they can be bought fresh they are boiled and then seasoned with malt vinegar and white pepper. They might be available alongside jellied eels, whelks and other traditional fare. Cockles are a popular type of edible shellfish in both Eastern and Western cooking
There are more than 200 living species of cockles. One group of cockles which has shells which are completely smooth, without ribs, is the genus Laevicardium. These are often known as egg cockles. The common cockle, more familiarly ribbed, Cerastoderma edule, is widely distributed around the coastlines of Northern Europe with a range extending west to Ireland, the Barents Sea in the north, Norway in the east, and as far south as Senegal. The dog cockle, Glycymeris glycymeris, has a similar range and habitat to the common cockle, but is unrelated. It is inedible due to its toughness when cooked. The blood cockle, Anadara granosa, not related to the true cockles, is extensively cultured from southern Korea to Malaysia.
Cockles are capable of 'jumping' by bending and straightening the foot. Consumption of raw cockles has been linked to hepatitis.
It is not possible to write about cockles without remembering the horrible disaster in Morecambe Bay in 2004. 23 Chinese illegal immigrants died. They were raking cockles and were unaware of the encroaching tide, famously treacherous in this Bay. It was shaming that these people were working in such a dangerous situation and not properly protected from the known risks.