Why Some Geckos Don't Stick
But a new study by Dr. Anthony Russell, a Professor in the Department of Biological Sciences at the University of Calgary, has found that geckos in desert regions of Africa have evolved different mechanisms for dealing with the varied terrain there.
Geckos that need to move faster over large flat rocks have pushed the toe pad forward on their feet, so it does not impede their ability to run. Those that now inhabit sandy areas have also reduced the use of toe pads and have also evolved webbed feet, so they don't sink into the soft surface. Geckos that burrow have completely lost the adhesive pad in favour of more robust legs, better suited for digging.