|Sand flats at mouth of Barron River, near Cairns|
|Sand flats at Ellie Point near Cairns with mountains in background|
The most abundant creatures by far on the exposed sand flats near the low tide line are sand dollars. Sand dollars feed by moving just under the sand surface and letting the plankton fall through the short felt-like spines to channels below which sweep the material from the top of the animal around the edge and into the mouth at the middle of the under surface. In some other parts of the world, sand dollars hide in the sand at low tide and feed on the surface at high tide and I will have to check if our local species does this myself, but my recollection is that they are always covered with at least a fine layer of material. The sand dollars may also be hoovering up diatoms that live in the sand and which come to the surface to photosynthesis at low tide.
|Sand dollar with a typical hat of sand|
|A sand dollar being eaten by two hermit crabs which are hidden by their shell houses|
|Little file snake at Cooya Beach, in the process of shuffling back into the sand|
|Close-up of head and rough skin, which is being rotated around the body to dig into the sand.|
Some creatures you see only once and this unidentified eel is an example, so it pays to have camera on you. The eel was able to retreat backwards into the sand. From memory, there were no yabby holes or any other gaps, just loose sand, so going into the sand backwards is quite a trick. The eel was however sucked out of the ground with a yabby pump which is how we got to see it at all.
|Unknown species of eel|
|A leaf-carrying or leaf porter crab|