Sharks have existed for approximately how long?

What unusual thing can the bull shark do?

What are baby sharks called?

What are shark skeletons made of?

After eating a seal or a sea lion, how long can a great white shark go without another big meal?

How many teeth can a shark have?

Which organ helps sharks to float?

What does the hammerhead shark use its unusually shaped head for?

How many shark species are there?