Where Do the Small Holes in Beach Seashells Come From

When people find shells with small holes on the beach, many assume they are traces left by humans. In fact, in most cases, they are the result of marine creatures preying on them. A related popular science article explains that carnivorous sea snails such as moon snails secrete acidic substances and then slowly drill with their radula, forming regular small holes in the shell before sucking out the soft tissue inside. These holes usually have smooth edges and are nearly perfectly round, often appearing in thinner parts of the shell. The article also notes that whelks, boring sponges, and other organisms may likewise leave different kinds of marks on shells, so whether a hole was caused by a moon snail still depends on features such as the hole’s shape and location. The article ends by reminding readers that when enjoying the beach, besides observing these interesting natural phenomena, they should also be aware of safety risks such as rip currents, sharp reefs, and some poisonous sea snails. When tide pooling, try to wear shoes and avoid touching wild shellfish of unknown origin.