Shark's skin isn't like other fish.  They don't have scales.  What sharks have are called dermal denticles.  Dermal denticles are like little teeth but,on their skin and not in their mouth.  In jaws two, when they were all in the water with the shark freaking out.  the shark rubbed against one of the girls stomach, it scratched her up.  the weird thing about that though, dermal denticles point back wards and not forwards.  and the shark wasn't swimming back ward.  sharks can't swim backwards.  I've pet a shark before at ocean world in crescent city, and it was cool! it was a leopard sharks, they are completely harmless.