Why Do Cockle Shells Have Holes?

Drilling predators such as snails, slugs, octopuses and beetles penetrate their prey's protective skeleton and eat the soft flesh inside, leaving behind a telltale hole in the shell. Trillions of these drill holes exist in the fossil record, providing valuable information about predation over millions of years.

What causes holes in cockle shells?

Within the snail's mouth is a hard, tongue-like structure called a radula. It is like a small file or rasp covered with tiny sharp teeth-like structures. With its radula, the Moon Snail drills a perfectly round, small hole through the bivalve's shell (and that is the hole you see).

What animal drills holes in clam shells?

Northern moon snails are the most common carnivores that drill holes in clamshells to eat the creature living inside. Moon snails live beneath the sand and feed upon clams by drilling a perfect circular hole a few millimeters in diameter, injecting acidic saliva, then siphoning out the meat.