Why do some sea snails wear shells with vivid colors and patterns?

Many marine snails build shells using calcium carbonate, and the shell’s color and pattern depend on the snail’s genetics, diet, and growth conditions. Some patterns may help camouflage the animal among rocks, coral, or sand, while others may make the shell harder for predators to detect or recognize. In several species, the shell surface also records growth changes over time, like a natural diary of the animal’s life. Because shell formation happens layer by layer, small changes in chemistry can create stripes, spots, or bands. Marine gastropod shells are therefore both functional and visually diverse.