Sanibel Sea School Blog

Sand Dollars: Dead or Alive?

November 5, 2015
Dead Sand Dollars

By Johnny Rader

We often find sand dollars on our beaches, and their beautiful skeletons make a great souvenir, but it’s illegal to collect them when they are alive. Live sand dollars play an important role in our local ecosystem by controlling populations of smaller invertebrates and serving as food for some larger organisms, including nine-armed sea stars.

Before you go beachcombing, be sure you can tell the difference between the skeleton and the living creature by keeping these three tips in mind!

1) Live sand dollars are members of the Phylum Echinodermata, meaning “spiny skin”.  As the name implies, they have tiny spines all over their bodies that resemble hair. These spines help the animal move along the ocean floor and bury itself in the sand. Hold the sand dollar gently in the palm of your hand and observe the spines. If they are moving, it is still alive. The animals lose these spines soon after they die.

The dead sand dollar on the left has started to fade.

2) Another way to determine if the animal is alive is by observing its color. Sand dollars can vary from a deep brown to a purplish-red color when alive. After the animal dies, the sun causes its color to fade, and the skeleton eventually turns silvery-white. People thought the skeletal remains (called the test) resembled silver coin currency, which is how the name “sand dollar” came about.

Sand dollars produce echinochrome, a harmless substance that stains your fingers yellow.

3) Live sand dollars produce a harmless substance called echinochrome, which will turn your skin yellow. Place a sand dollar on your open palm and leave it there for a minute. If it leaves a yellowish stain, the animal is alive.

Sand dollars can’t survive out of the water for more than a few minutes. If you find a live one, return it to its home by placing it gently on the sea floor, so it can continue to play its important role in Sanibel’s ecosystem. 

These dead sand dollars have been bleached by the sun and are fine to take home and enjoy. Be careful when transporting them, they are fragile!

If you are lucky enough to find a dead sand dollar, you can take it home to display proudly among your beach treasures.

Thank you for helping us care for the creatures we share our island with!

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