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A Moon Snail's Life Cycle

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Moon snails are predatory sea mollusks that are as abundant in tropical waters as they are in arctic waters. Nearly 300 species of moon snails exist. They have a round shape and are a blue-white color. Moon snails have a large shell and an even larger foot with which they burrow in sand or travel across it.

Sand Collars

When a female moon snail is getting ready to lay her eggs, she prepares a collar made of sand, in which she keeps and protects the eggs until they are ready to hatch. She sinks to the ocean floor and hovers above the sand. She then covers herself with her large foot, which is covered in cilia. She uses the cilia to grab grains of sand, with which she covers her entire body. The female then secretes mucous, which hardens and encases her in the sand shell.


A female moon snail can produce thousands of eggs at one time and lays them at night. She uses the cilia on her foot to distribute the eggs between herself and the sand collar she’s made. She then secretes a separate layer of mucous to form another layer of hardened sand, which separates her from the eggs, so she can leave them protected while scavenging for food.

Planktonic Larvae

After a few weeks, the eggs begin to hatch and planktonic larvae emerge. As they hatch, the sand collar disintegrates around them.

Growing Pains

Once their shell begins to form, the young moon snail travels to the ocean floor in search of food. As the shell grows, it forms around an axis, creating a tube, which gives it a unique spiral shape. The tube that results when the shell forms is called an “umbilicus.”

Life Span

The moon snail lives anywhere from two to seven years. When the it dies, its shell gets discarded and sometimes washes up on the beach. More often, however, hermit crabs will take the shell and use it for protection since they cannot form their own shells.