The Amazing Sand Dollar
Sand dollars are a type of invertebrate related to the sea urchins, sea stars, and sea cucumbers.
Sand Dollars are almost all skeleton. Most people are familiar with the smooth exoskeleton of a sand dollar found along beaches. However, the live sand dollar has a rather velvety "coat" made of densely packed, tiny, dark purple spines.
The timid sand dollar lives on the sea floor in large colonies. They use their fuzzy spines, aided by tiny cilia, to maneuver, as well as transport food particles along their bodies to a central mouth on their underneath side.
In quiet waters, the crafty sand dollar will stand on its edge to increase the odds of catching food. However, when ocean waters are rough, they lie flat and grip the sand for support. Young sand dollars will ingest sand to give them more weight and ballast to withstand currents.
The sand dollar's mouth has a jaw with five teeth-like sections used to grind up tiny plants and animals. Sometimes a sand dollar "chews" its food for fifteen minutes before swallowing. It can take two days for the food to digest.
Scientists can determine the age of a sand dollar by counting the growth rings on the plates of the exoskeleton, much like counting the rings on the cross-section of a tree. Sand dollars usually live six to ten years.
For more interesting and fun information on the amazing sand dollar, please explore the following references!
*Note: The above information was taken from the Monterey Bay Aquarium website.