The sand dollars found on beaches are the skeleton, or test, left behind by living sand dollars. Sand dollars live in the sands of shallow waters, where they burrow into the ground for food.
Live sand dollars have short spines covering their bodies that can be brown, gray or green. Sand dollars are in the same family as sea urchins and are also related to sea cucumber and starfish. These animals eat small particles found in the sand with their five jaws. There are both male and female sand dollars, and they reproduce by releasing eggs and sperm, which grow into larvae.