The giant Lewis’ Moon Snail - Neverita lewisii (Syn. Euspira lewisii)

The giant Lewis’ Moon Snail - Neverita lewisii (Syn. Euspira lewisii)

Lewis’ Moon Snail, Neverita lewisii (Gastropoda - Naticidae), is a huge sea snail native to the Pacific Ocean coast of North America, from Canada to Baja California, Mexico). This is the largest of the moon snails, with shells up to 13 cm in diameter, however a fully expanded animal is several times larger than its shell. The snails plough forward with a foot just below the surface of the sand. When extended, the foot can measure over 30 cm in diameter.

Moon snails feed mostly on clams, mussels, or other mollusks. They are “boring predators”, meaning that they drill through the shell of their prey and ingest the tissue inside. In order to drill a prey item successfully, they must first detect and immobilize their prey, cover it in a mucus sheath and then transport it into the sediment to be drilled. Moon snails use a combination of an acidic enzyme and a “rasping tongue”, the radula, to penetrate their shelled prey. The radula, located at the end of the proboscis, scrapes the surface of the shell as the proboscis rotates 90 degrees, resulting in a fairly round and smooth borehole with an inner and outer edge. The accessory boring organ, located in the snail’s foot, secretes the acidic enzyme to soften the shell of the prey.