After grabbing a sand dollar at the beach, this woman had a startling realization. It was unlike any she had seen before. Sand dollars are amazing creatures that are in fact alive despite seeming like they do not move. This video shows that sand dollars do move, as well as the difference between a live and a dead sand dollar.
In living sand dollars, the test (rigid skeleton/shell) is covered by a skin of velvet-textured spines which are covered with very small hairs (cilia). Coordinated movements of the spines enable sand dollars to move across the seabed. The velvety spines of live sand dollars appear in a variety of colors—green, blue, violet, or purple—depending on the species. Individuals which are very recently dead or dying (moribund) are sometimes found on beaches with much of the external morphology still intact. Dead individuals are commonly found with their empty test devoid of all surface material and bleached white by sunlight, which are sand dollars we collect from beaches.