Some lizards swim through sand as though it were water. Why?

AFICIONADOS OF “Dune”, Frank Herbert’s novel about a planet covered by Sahara-like desert, will be familiar with the idea of animals that swim through sand. Giant worms which do just that are a feature of the book. Back on Earth, though, there are sand-swimmers, too. And these ones are real. At least eight groups of lizards have a habit of diving headfirst into sand, if it is available, and making paddling motions with their limbs to carry them below, as if they were submerging themselves in a body of water. The question is, why?Obvious hypotheses include evading predators and controlling body temperature. However, Ken Toyama of the University of Toronto has a third: that the animals are ridding themselves of skin parasites. And he has data to back his theory up.