On the seafloor, sand dollars have fuzzy spines and tiny hairs that ferry food particles along their bodies to a central mouth on their bodies. They can also capture plankton with spines and pincers.

The mouth has a jaw with five sections to grind up tiny plants and animals. It may take nearly two days for the stomach to digest the food.

Sand dollars also use their spines to move along the bottom of the sea.

Depending on the speed of the water in their habitat, they will either stand on end, lay down, or even bury themselves in the sand. They have acquired this adaptation in order to stay in one environment. Some adults in faster waters will even grow heavier skeletons in order to weigh themselves down in the water. Because juveniles are not as heavy as their parent, they will consume heavy sand particles to weigh themselves down.