What are Sand Dollars?

Site Navigation

Home Page

   Where do shells come from?
   Is seawater similar to blood?
   Picking up seashells
   What are starfish?
   Do sharks have skeletons?
   What are sand dollars?
   What are seahorses?
   What are "flying fish"?
   How navigate on the ocean?
   More legs than an Octopus?
   Fish training
   Can I drink seawater?

Additional Resources
   Seashell Identification Guide
   Conchologists of America
   Waikiki Seashells
   Training Fish

Featured Products
   Marine GPS with MOB Key

Privacy Policy Page

Contact Us

What are sand dollars?

A sand dollar shell looks sort of like a round white coin, which is where it gets its name. When you see a sand dollar that's washed up on the beach, it usually appears to be a round, white circular disk, typically one inch to four inches in diameter. When they're alilve they're actually a dark color, covered with short dark spines that look almost like fur. These spines are moveable, and the sand dollar uses them both to move around on sea bottom and to push small pieces of food to its mouth.

Just as the common sea star or starfish has five arms, most sand dollars have a pattern of five sets of pores on them. Those are used to move sea water into the sand dollar's body, which is then pumped to where it's needed to aid in movement or other internal functions.

Sand dollars like smooth sandy or muddy ocean bottoms. They mainly live in shallow water, near land.

Sand dollars reproduce by releasing eggs and sperm into the water, where they join and develop into free-swimming larvae. These develop through several steps until the hard skeleton starts to form. Then they drop to the bottom and live the rest of their lives there.

If the water is fairly calm where they live they will often stand on edge, partly in the mud and partly exposed to the clear water. If they live in an area with strong currents, sand dollars can hold their position by burrowing into the soft bottom. They will also swallow sand grains to build up their weight so they don't get washed away!

If you find a sand dollar skeleton on the beach (looking at low tide is best), and it's white (so you know it's not still alive), and the rules for that beach say it's O.K. to take it, then you may. But be aware that it needs to be treated very carefully to be preserved.

At this stage they're very fragile, and may still have some tissue from the animal's body inside.

To preserve sand dollars, here's what to do:
  • Soak it in fresh water. As the water clouds up and starts to smell, drain it off and pour in more.
  • Keep doing that until the water stays clear.
  • Put the sand dollars into a solution of two cups of fresh water and one cup of bleach, and let them soak for about a quarter of an hour.
  • Rinse them thoroughly with fresh water, over and over until most of the bleach smell is gone, then let them dry.
  • At this point there should be no more organic matter in the sand dollar, just the shell should remain.
  • Now mix a 50:50 solution of fresh water and "white glue" -- Elmer's Glue or a similar glue.
  • Brush that over the sand dollars on the top sides with a soft brush, very gently. They're still very fragile, and this will give them strength.
  • Let the glue solution on the top side dry, then turn them over and apply the glue to the other side.
  • After that's all completely dry they should be strong enough to handle. If not apply another coating of the water/glue mixture.
  • You're done! Now they can be handled, made into jewelry, etc.

Back to our List of Article Summaries

Murex Ramosus Seashell


Sand Dollar

Pearl Nautilus Seashell -- Split

Jungle Starfish

Lambis Chiragra Spider Conch Seashell

Website Copyright © www.SeashellsAndSuch.com 2007 -- all rights reserved.