The dog whelk, dogwhelk, or Atlantic dogwinkle, scientific name Nucella lapillus, is a species of predatory sea snail. This carnivorous snail has the ability to burrow through the shells of it’s prey which includes mussels and barnacles.
The shells are usually a whiteish-grey but can be a wide variety of colours.
The dog whelk can be used to produce red-purple and violet dyes that were much prized in the ancient world. The Venerable Bede mentions that in Britain “whelks are abundant, and a beautiful scarlet dye is extracted from them which remains unfaded by sunshine or rain; indeed, the older the cloth, the more beautiful its colour.”
They can only survive without water for a limited period of time as it will become desiccated and die if out of the water fro too long.