A male sand dollar releases sperm and a female sand dollar releases eggs into the tropical waters where they live. The sperm and eggs meet, and fertilization occurs. Fertilized eggs grow into larvae that join the plankton, the tiny plants and animals swept along by ocean currents.
If the larvae survive, they grow into juvenile sand dollars and fall to the bottom of the sea. If the conditions are right, the juvenile sand dollar takes between 16 and 28 days to grow into an adult sand dollar. The adult then burrows into the sand and feeds on organisms found there, such as diatoms. They use their strong jaws to grind the sand for food.