Creature Feature – Sanddollars


I love sanddollars, they are so exquisite.  The picture here is what most of us think of when we picture a sand-dollar.  I have not had too much bringing these up to shore in one piece so I wanted to find out a little more about them.  Sand dollars are echinoderms (which means spiny skin) like the sea urchin and starfish. One of the reasons I have been having a problem with these staying whole is the ones I have found to date are all dead.  They are extremely fragile and break when the air hits them. I did not realize that live ones are a different color.  We have all seen sand-dollars in the tacky tourists shops.  They are found in glasses, in jewelry and even in lamps.  Once they have died, their hard outer shells will remain and they are bleached white.   If you live close to a saltwater beach, you can collect your own sand dollars and preserve them yourself using household supplies. Stay tuned tomorrow as I will feature how to preserve these.

Sanddollars are also called sand cakes, cake urchins, pansy shells and sea cookies depending on what country you are in.  The name sand dollar most likely originated from beachcombers thinking it was a washed up silver coin.

First, let me share with you a little bit about what I found out about them.  Quite interesting as I was not aware of how these creatures lived or moved about.

The sand dollar has a rigid skeleton.  Live sand dollars look like fuzzy cookies. They are covered with many short spines.  This skin is called a test.  You can see the radial 5 pattern on the remains of a skeleton.  But did you know in live sand-dollars that the have a velvet like spines on the outside?  These spines can be purple, green, blue or violet depending on the species.  They are made up of calcium carbonate.  Apparently in Florida they are dark green.  The spines are covered with little hairs on the outside called cilia (tube feet).  These little hairs are how this gorgeous guy gets around and how he moves food into his mouth.   Besides the special tube feet on their tops, sand dollars also have tube feet on their undersides. Sand dollars do not push their stomachs out or swallow animals with large shells. Instead, sand dollars sift through the sand and catch tiny organisms with their sticky tube feet.  When you find one on the beach, the outer velvety skin is missing and it has been bleached a white color by the sunlight.  The sanddollar’s mouth is on the bottom in the middle of the radial pattern.

Sanddollars have evolved through time.  They originally lived their lives on the top of seabeds but now they burrow below the sand, most probably for protection.  They live between high tide and low tide  (intertidal zone) up to the area below low tide.  For divers, most sanddollars are found between 30 and 40 feet  They partially burrow in leaving an edge poking up in the sand slanting in the current’s direction.   It can burrow due to the spines it has on the underside.  The little hairs allow the critter to move along. The sanddollar will eat tiny critters floating in the water like little diatoms, algae, copepods and even crustacean babies.

The sanddollars major predators are skates, stingrays, starfish and sea snails and flounder.

Sanddollars have been known to live up to 13 years if they are in protected waters but if they get turned over, they will die because they are unable to turn themselves right side up.  Perhaps this is the reason why we see so many pieces broken off after a storm up on shore.

If you break open a test, there are many hard, loose, little, white pieces.  These were the teeth of the Sand Dollar.

Sanddollar folklore:

For Christians there is the legend of the sanddollar.  I know when I was growing up in the Babtist church that many housewarmings and other little events, they would give a sand-dollar.

There’s a lovely little legend
that I would like to tell,
of the birth and death of Jesus,
found in this lowly shell.
If you examine closely,
you’ll see that you find here,
four nail holes and a fifth one,
made by a Roman’s spear.

On one side the Easter lily,
its center is the that appeared unto the shepherds
and led them from afar.
The Christmas Poinsetta
etched on the other side,
reminds us of His birthday,
our happy Christmastide.

Now break the center open,
and here you will release,
the five white doves awaiting,
to spread Good Will and Peace.

This simple little symbol,
Christ left for you and me,
to help us spread His Gospel,
through all Eternity.

Inside the teeth were supposed to signify little white doves. The gray Sand Dollar represents LIFE…the white one the RESURRECTION.

I have also heard that if you find a sanddollar, you found some loose change from Poseidon’s treasure vault or that you found some coins lost by mermaids or the people of Atlantis.

‘Aristotle’s lantern’ has been discerned in the distinctive perforations of keyhole sand dollars.

Stay tuned tomorrow as I will feature how to collect and preserve these magnificent creatures.

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About daniellesdives

diving enthusiast
This entry was posted in Creature Feature, Technical tips, info, or other useful thoughts and tagged , , , , , , , . Bookmark the permalink.

3 Responses to Creature Feature – Sanddollars

  1. Pingback: Creature Feature – Sanddollars – How to collect & preserve them | Danielle's Dives Blog

  2. Denise says:

    This has given me so much information .i really enjoyed learning about them thank you for posting all this helpful info.denise green

  3. unnamed says:

    wow! super!

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