While walking on the sandy beach in the intertidal zone, you may see various shells and other sea life, but you probably will not spot the Moon Snail. It prefers life burrowed in the sand, so it is rare that you get the chance to see the mysterious Moon Snail. At first glance, they may seem small and ordinary, but upon holding one, you may feel small muscle contractions as a thick gel begin to ooze from underneath the soft, silky foot. Kids and adults alike will stare in amazement as they start to expand their mantle to cover your entire palm, and if you’re lucky their antennae will peak out of their comparatively small shell. Once you get to know more about this member of the Nacticidae family, you may want to get an even closer look at one in its natural habitat.
Moon Snail Basics
A moon snail shell is approximately the size of a half dollar with a large, purple mantle. Its shell is only 2.25 – 5.5 inches across, but the “body” or mantle can extend to nearly four times that size. Unlike the common hermit crab who shops around for their shells, moon snails keep the same shell their whole life.
The foot, or portion that touches the ground, is covered in mucus and tiny hairs, called cilia, which aid in locomotion. Moon snails excrete a clear, thick, sticky slime that serves two purposes: movement and protection. It is also used when creating the nests for its eggs.
Moon snails spend the majority of the time burrowed in the sand on the shore. However, in the winter, they move to deep waters. They also lay their eggs on shore, creating towers made of layers of sand stuck together with mucus.
Have you ever seen washed up shells that have a perfectly circular hole cut out? They make for a great necklace, and you can thank moons snails for your new shell necklace. Moon snails eat a variety of clam, mussels, and other mollusks. Sometimes, they even eat other moon snails. To eat, they suction to their prey’s shell and use their radula, or tongue, to drill into it while simultaneously secreting the enzyme carbonic anhydrate, which is believed to soften the shell for easier drilling. Once there is a hole, the moon snail can digest its well-deserved dinner.
Moon Snail Anatomy
Life in the intertidal zone is a constant battle, as animals must be able to endure long periods of crashing waves, varying levels of oxygen, and the constant threat of predators. To cope with the challenges of their habitat, the moon snail has developed unique anatomical structures.
Their skin is incredibly delicate, so the mucus serves to protect it from diseases and irritants found in the environment. The moon snail’s mucus serves not only to provide a path to travel on but also as a thick adhesive that aids in suctioning to rocks, so they do not wash away with the tide. An amazing feature of moon snails is how they can increase the size of their mantle by absorbing extra seawater. Their enlarged mantle enables them to dig under the sand or rocks to search for prey.
When they feel threatened, Moon snails can greatly decrease their body size and completely retract into their shell. However, they have few natural predators. The worst predator is humans who trample them, pollute their home, and collect them as treasures.
A moon snail probably won’t make the best addition to an aquarium. They will eat every clam you have, and breeding is almost impossible because the small size of the larvae means they will not likely survive. Not to mention, they will leave mucus everywhere. It is best to see them in nature where they belong.
Remember, if you are ever tide pooling and come across one of these guys, feel free to gently pick them up to get a closer look. However, remember to put them back exactly where you found them.