The Tun Shells of the Tonnidae Family are medium to large shells that have thin but strong construction. They are named after the wine casks, known as tuns. The shells have a large body whorl, a low spire, a short siphonal canal and a large aperture with most being sculpted with thick spiral ribs. The animals are often too large to retract into their shells and they lack an operculum.
Tun Shells are primarily, but not exclusively, tropical in distribution. They are found over and within sand substrate from the intertidal zone to depths of several hundred feet. They bury themselves during the day and emerge at night to prey upon bivalves, crustaceans, fish and sea cucumbers. There are thirty-four global members of the Tonnidae Family and which two species are found in the coastal waters of Baja.