The Striate Piddock
The inch-long Striate Piddock, Martesia striata (Linnaeus, 1758), uses its rough shell to bore through wood. Piddocks use the front end of their shells in a semi-circular motion to drill through the wood, creating a long, cylindrical hole that is occupied for life by the animal. To collect their shells, look for “Swiss cheese-like” driftwood with the characteristic boreholes indicative of their presence.
The Striate Piddock (left) and driftwood bored by Piddocks and other Clams, found on Sanibel.