The Pleasantly Plump Sand Dollar Urchin

Habitat: South-west Pacific and eastern Australia
Status: Not Listed

So the creature presented here may look like an obese sand dollar and well, you would be right in thinking that.

This is the Sand Dollar Urchin (Clypeaster australasiae) which is an uncommon resident of Australian waters. It comes in shades of brown ranging from a dark hue to a creamy, sand-like color. The Sand Dollar Urchin is covered in tiny little spines which are in turn covered in hair-like cilia. Using coordinated movements of its spines, the Sand Dollar Urchin is able to move across the sea floor eating little microorganisms it might find along its way. You can watch this time-lapse video of a different species of sand dollar doing just that:

Did you know that all sand dollars are actually species of sea urchins? They’re just much flatter, though in some cases they’re raised and a bit more burly (as is the case here). No matter the shape, they all belong to the order Clypeasteroida.

If you happen to find a sand dollar on the beach make sure that it’s not alive before taking it home (though, I really don’t advocate moving creatures from their habitats in general). Dead individuals will lack all pigment and won’t have their velvety spines any longer. Instead, they will simply be white skeletons, bleached from baking in the sun.