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.   

HARMLESS SHARKS

Not all sharks are dangerous. Sharks like whale sharks and leopard sharks are completely harmless. Whale sharks get up to about 50 ft. long. Scuba divers can catch rides on their backs. Whale sharks only eat plankton. They have thousands maybe evan millions of teeth, but every single one is totally dull. Great whites are not really dangerous but they can be. They're the type of shark that don't attack people unless the shark is hungry or if the human is bleeding.

FRESH WATER SHARKS

Bull sharks can live in fresh water and salt water.  Bull sharks are found most in the Mississippi river, and  the Amazon river.  Bull sharks are pretty aggresive.  They get up to about 5 to 6 ft. 

SAVE THEM!

Sharks are very close to being extinct.  People who make shark fin soup catch sharks, cut off their dorsal fins and throw them back into the water to either be eaten or to bleed to death.  I've eaten thresher shark before and it tasted like salmon.  Thresher sharks are not dangerous to people unless hit by their long tale that's about the size of their body!  You can save sharks by saving water. Turn off your faucets when you're brushing your teeth.  And when you're doing the dishes, put the water plug in instead of having the water on the whole time.

Sharks don't just have one layer of teeth, they have about five layers of teeth.  whenever a shark loses a tooth a new one moves to take it's place.  shark teet are very sharp.  Mako sharks teeth are curved back so if the thing it's attacking tries to pull out of the sharks mouth it's teeth will just stab deeper in the fish.  The now extict Megelodon shark had a jaw that could fit a full grown man!  Whale sharks have thousands of teeth, but all thoughs teeth are dull.  Tiger sharks have sarated teeth.    

PUPS

Not all sharks lay eggs, in fact more sharks give live birth.  Shark eggs are usually called mermaid purses.  Baby sharks are called pups.  Small sharks can be very vonerable too octopus other sharks and orcas.  Orcas are one of the enemies of sharks.  Who would think that a shark would be able to eat an octopus very quick but octopus can also eat a shark.