Facts About Sharks – The head of a shark is cone-shaped and large. In contrast, they only have small eyes on the sides and their nostrils are on the top of the snout. A shark has an enormous number of spare teeth that are located on the inside of the jaw edge. This is also necessary because when they attack teeth are regularly broken and are immediately replaced by one of the spare teeth that appear in the rows behind the front teeth. This way, the sharks always have razor-sharp teeth. The shark gets oxygen from the water through its usually 5-gill slits. Sometimes there are 6 or 7-gill slits. These occur on both sides of its head. Many sharks have to move continuously to get oxygen.