Sand Dollar (Clypeasteroida)
Size – On average they are between 3 and 4 inches (7-10cm)
Sand Dollars are sand-grubbing Sea Urchins in the Order, Clypeasteroida.
Some of the less-flat Sand Dollars in the Order are known as Sea Biscuits.
All of them possess what is called a “test,” which is a rigid skeleton and basically means a spherical hard shell. They can live up to 10 years and their age is often determined by how many rings on their plates (on the test.)
They can be found on the sandy seafloor of shallow coastal waters nearly worldwide.
They are unable to survive very long out of the water.
Their mouth has a jaw with five teeth like rows or sections to grind up Crustacean larvae and algae.
They use their small spines for digging and burrowing into the sand. They use their holes on their body similarly to a pressure drainage channel to prevent them from being whisked away by the waves.
Sand Dollars are an echinoderm of the Order, Clypeasteroida.
They don’t have many predators due to their lack of edible parts and hard skeletons.