Have you ever found shells with holes on the beach? Did you wonder how they come about? Pierced shells are more than just a natural wonder. They tell the tale of predatory behaviour in the ocean. Also they play an essential role in maintaining the balance of the marine ecosystem.

I love walking along the beach. It is relaxing and offers the chance to discover natural wonders. Among the various treasures that the sea deposits on the shore, I often come across shells with perfectly round holes.

shells with round holes

Why do shells have holes?
Holes in shells are usually caused by marine predators, such as mollusks or sea snails and some types of octopuses. These predators pierce the shells to feed on the molluscs inside. They use a combination of acids and radulae, a kind of toothed tongue, to pierce the shell and reach their meal.

The role of naticidae
Naticidae, also known as moon snails, are masters of the art of piercing shells. These mollusks produce an acid that softens the shell of their prey, allowing them to dig a perfectly round hole with their radula. This process can take several hours, but it is an effective method that allows Naticidae to feed on molluscs such as clams.

Octopus action
Octopuses can also pierce shells. Their method is slightly different. They use their sharp beak to create a small hole, through which they inject a paralyzing toxin and digestive enzymes. These liquefy the body of the mollusc, allowing the octopus to easily suck it up.

The ecological importance of shell holes
Shell holes are not only an example of the struggle for survival in the marine world, they also play an important role in the beach ecosystem. Shell holes, once emptied and washed ashore, become part of the coastal environment, contributing to the formation of sand dunes and providing habitat for small land creatures.

Leave stones and shells on the beach, otherwise the coasts are at risk
The law – in this case the Navigation Code – says it loud and clear. Anyone who removes shells, sand and stones from the beach is committing an offence punishable by an administrative fine of up to 9,296 Euros. There are several articles published by scientists in support of this subject. Sand, pebbles, shells and the like must stay where they are. They create homes for many living beings and represent a natural protection for houses and infrastructure near the sea. Beaches are able to absorb the energy of the sea waves. For this reason, the removal of pebbles, sand and sediments makes the beach less capable of acting as a natural barrier to flooding and erosion.

Between nature and legend…
Walking along the beach it is not unusual to come across “flat shells”. They are also known as eyes of Saint Lucia. They are a couple of centimeters in diameter and have a rounded shape. Flat and white on one side they are convex and colored (usually orange) on the other. The flat side has a characteristic spiral relief. The eyes of Saint Lucia are so beautiful that they are sometimes used to make pendants, necklaces and other small jewellery. Even if they should be left in place on the beach like real shells. People who live in close contact with the sea sometimes wear them as good luck charms. Before telling the legend, let’s first look at what they are.

What are the eyes of Saint Lucia?
The eyes of Saint Lucia are the opercula (door) of a gastropod mollusc (slug, snail, invertebrate), common in the Mediterranean. Its scientific name is Bolma rugosa. The operculum (door) is a rigid structure that serves to close an opening of a living being. In the case of gastropod molluscs it is positioned on the back of the foot, the fleshy and muscular part that these animals use to crawl on the ground. In practice, when they retract into the shell, they close the opening with a very hard and resistant structure – often calcified – to prevent potential predators from having easy access to the soft tissues. It is like a real “armored door” with a protective function.

The spiral, radiate and striated shell is grey to brown in colour. Its maximum size is about 7 centimetres, although they are generally smaller. The mollusc is widespread throughout most of the Mediterranean Sea and in the Atlantic. It lives mainly on rocky seabeds where it feeds on debris. When it dies, its calcareous operculum (door) comes off and currents and wave motion carry it s easily to shore.

Eyes of St. Lucia

Eyes of St. Lucia

Where does the name ‘Eyes of Saint Lucia come from?
The name links to a legend about the life of a Syracusan martyr. According to this story, the woman gouged out her eyes and threw them into the sea to fully embrace her devotion to the Virgin Mary. The reason for this devotion was the recovery of her mother from an incurable disease. According to the story, the Madonna decided to reward the woman’s faith with new, bright and luminous eyes. Saint Lucia whose name comes from the Latin term lux or light is the patron saint of sight. Saint Lucia is also considered the protector of the blind and eye doctors. She is often invoked by those who suffer from eye diseases. According to some maritime beliefs, pendants made with the eyes of Saint Lucia help to defend oneself from eye diseases and the evil eye. Shiva’s eyes, Naxos’s eyes and others are names for eyes of Saint Lucia in other countries. where they always have a protective connotation.