Sharks, Rays and Skates Research

Sharks, rays, and skates cruise the waters around the reefs that fringe Australia. These animals are sacred to the Yolngu people of Northern Australia, who believe shark ancestors helped create the world. Sharks do not have swim bladders, and if they were to stop moving they would probably sink to the bottom of the ocean; therefore, they are usually constantly in motion. Sharks usually are scavengers, eating injured fishes, carrion, garbage, and other waste from ships as well as animals such as seals, turtles, birds, whales, crabs, and a wide range of fishes. The whale shark is the largest shark and also the largest fish in the sea, measuring up to 15 m (49 ft) in length; the cookie-cutter shark measures less than 50 cm (19 in) in length. Usually there are five gill slits that lie behind the head. The tail's symmetry is termed cercal because of its irregular shape. Rays are actually nothing more than flattened out sharks. They are the "birds" of the sea. They can be seen flying gracefully through the water as effortlessly as a bird flies through the air. Some rays are capable if inflicting painful stings with their tails. Others, such as the giant manta, can grow to enormous proportions but are completely harmless to man. The skate is a member of the ray family but is distinguished from most other members of that family in that they lack a tail barb or stinger. Skates are a kite shaped fish that have a flat body and two wings. The wings are the only part of the fish that is consumed. Skates, like sharks, excrete excess urea through their skin and if not handled carefully after capture will smell of ammonia.