Sand Dollars in the sand.

“Ha” you might say spotting a beautiful Sand Dollar on the beach.  They are so delicate yet there it is on the sand having arrived there by surviving the crashing waves.  One of life’s delicate treasures delivered to you.

   Sand dollars, also known as sea cookies, snapper biscuits in New Zealand, or pansy shells in South Africa, are a flattened, sand burrowing sea urchins. These small ocean animals can be found in temperate and tropical waters.  Being in the echinoid class, the sea urchin class, the Sand Dollars exhibit radial symmetry.  Usually, pentagonal symmetry where it is made up of 5 equal/nearly exact sections. These are organized around the mouth. It is also responsible for the unique flower shape design on their back. These flower design are 5 pairs of petal-like formations made from the pores on their back.These pore formations are perforations in the endoskeleton of the sand dollar and are used for gas exchange.  We might say breathing.

  The skeleton or “test” of the animal is what you find washed up on the shore line.  The test contains calcium carbonate plates arranged in way that give these animals their round shape. These plates are also used to tell how old the sand dollar is. Similar to counting rings on a tree, you can count the rings on the plates of a sand dollar.

       When living the test is covered with a velvet textured skin with spines. This skin can appear to either have a green, blue, violet, or purple tent, which is dependent on the species. The spines are covered by cilia that they use to carry food up to their mouths which are located on the underside right in the center.  Sand dollars also use these cilia to propel their bodies leisurely around the ocean floor. These little creatures spend their days coasting the ocean floor usually in large groups.

Sand dollars have relatively easy life. They coast the ocean floor finding food, they don’t worry about anyone munching on them, they keep close to their friends and enjoy the warmer waters.  I could spend a day in the life of sand dollar, how about you?

Leave a comment

All comments are moderated before being published