Cartilige does not fossilize, and therefore the only clue as to sharks from the past are teeth. Yes it is true that sharks do in fact have very good eyesight. In fact, sharks can see extremely well in dark lighted areas, have fantastic night vision, and can see colours. Avoid wearing bright colours in the water, such as oranges and yellows, as sharks can indeed see them. It has been observed that sharks can go up to approximately 6 weeks without feeding, and the record for a shark fasting was observed with the Swell Shark, in which it did not eat for 15 months.
Sharks are fish.
They live in water, and use their gills to filter oxygen from the water. Sharks are a special type of fish known because their body is made out of cartilage instead of bones like other fish. Sharks are omnivorous, which means they eat both meat and vegetation. Sharks will eat anything, and if there is not an abundant supply of meat in the area, they will resort to eating sea vegetation. The largest shark of them all, the Whale Shark is mainly a plankton feeder.