Sharks & Rays
Information about Sharks:
Sharks are a predatory fish that can be encountered in nearly every part of the world’s oceans. These members of the class Chondrichthyes do not have bones, but rather have cartilaginous skeletons in their streamline bodies. Their teeth therefore are embedded in the gums, and over the course of a lifetime are replaced over and over. They are an ancient species and can be traced back about 420 million years ago. There are about 440 different species of sharks alive today, the smallest being the dwarf laternshark (about 7 inches long) and the massive whale shark which can grow to an astonishing 40 feet.
Most sharks are exclusively saltwater although occasionally some species can venture into freshwater or brackish water. There is a famous incident in 1926 in which a Great White Shark, for reasons unknown, heading upstream many miles into a river in New Jersey where it attacked and killed a number of humans. But the vast majority of sharks pose little or no threat to humans. Sharks have an excellent sense of smell. Some species are able to detect blood in as little as one part per million in seawater.