What have scientists learned about sharks?

Answer 1

More people are killed each year by pigs than by sharks More people are killed by bee stings than by being killed by a shark More people are killed by being hit on the head by a coconut than being attacked by a shark.

Answer 2

Dolphins can scare sharks by tapping it rappidly with its tail. Narwhals exisit! they eat fish, squids, shrimp, and 5% humans! dolphins can live in rivers, which is called fresh water dolphin.

Answer 3

Apart from the obvious - that sharks are cold-blooded vertebrates, classified as fish, which breathe through gills rather than lungs - there are many things scientists have learned about sharks.

Sharks generally have five rows of teeth with about 46 teeth in each row. Depending on the species, they have an average total of 230 teeth. For example, Great White Sharks can have 50,000 teeth in a lifetime. These teeth are set in layered rows with 5 to 15 in both upper and lower jaws. The teeth do not have a root so they break easily. The teeth are arranged in rows of 5-7 teeth like a conveyer belt. When a tooth falls out from the front the tooth from the next row moves up to take its place. At any time a white shark will have about 300 teeth in various stages of development within its jaws.

There are over 470 species of sharks. Many species of sharks are apex predators, meaning that they are at e top of the food chain. Unfortunately, this also means that they are hunted in large numbers by Man as killers. Because they have low rates of reproduction, and the young sharks grow slowly, this means their populations may be threatened or, in the case of some species, endangered.

Sharks have special types of placoid scales known as dermal denticles. These are different to normal fish scales, being tiny tooth-like structures which protect the shark from injury and parasites.

A great many more scientific facts about sharks can be found at the related link below.