If you visit the beach, you may stumble upon flat, white discs, with a little star/flower on them. These are known as “sand dollars.” They get their name from the fact that their sun-bleached remains in the sand resembled large, silver coins to early beachgoers. In reality, these “objects” are the remnants of a once-living organism belonging to the sea urchin family, which are relatives of starfish and sea cucumbers.
Because they’re most usually found after they’re already dead, it’s easy to think of sand dollars as being an inanimate object rather than the remains of a once-living creature.
The video below, presented by the YouTube channel Sea Something, let us take a rare close-up look at a live sand dollar, as well as what it looks like compared to an already dead one.
As you’ll see, the dead sand dollar has visible grooves and a clear opening on the underside. The living sand dollar, however, has a blackish skin on its exoskeleton, and the underside is covered in a writhing mass of tiny bristles, known as cilia, which can vary in color drastically from one species to another.
These microfine bristles also help trap the microscopic organisms the sand dollar feeds on and moves them towards its mouth at the center. Also, by coordinating their movement, the sand dollar uses them to move along the ocean floor.
Enjoy, and be sure to SHARE this fascinating video with your friends and family.
Have you seen an alive sand dollar before?