Hey Tom,
I have no idea
They are called Sandfish because it looks like they "swim" through sand. They are completely adapted to life on loose sand. Their hands are like shovels or spoons, and their heads are shaped so they pierce right in to the sand. When they see me, they literally disappear in to the sand in less than a second.
The largest one will come out around my wife. My wife can fold laundry, while watching T.V., right in front of it, and it won't hide. God for bid my son, dog, or myself, should put so much as an elbow in the room and....POOF!!.... gone! And I'm the one who feeds it!! It makes taking pictures impossible
