Dolphins :: essays research papers

DolphinsDolphins argon mammals closely related to whales and porpoises. Dolphinshave a powerful and streamlined body. They are found in all seas and oceans.Dolphins kindle be told apart from porpoises by their nose, which is beaklike, and similarly their conical teeth. Porpoises have a flatter nose, sharper teeth, and amore solid body.There are 32 known species of dolphins. The bottle-nosed dolphin isoften the species used in aquatic shows. The common dolphin inspired manyMediterranean folk lores. Both of the dolphins above face in open waters,usually around cruise ships. They like to show off around the boat.There are also freshwater dolphins that live in rivers of Asia and SouthAmerica. The Buffeo dolphin has been spotted up to 1250 miles up he Amazon River.The buffeo is the smallest of all dolphins averaging about 4 feet. Thebottlenose is closer to 10 feet. The killer whale, which is also considered adolphin, can grow to be 30 feet long. The pilot whale is also considered adolp hin.Dolphins were erst hunted by commercial boats for the small sum up ofoil that can be extracted from their body. This oil is used to lubricate smallparts in watches. Cheaper oils have been found, so dolphins are not hunted forthis debate anymore. Dolphins can be caught in tuna fish nets by accident. Sincedolphins have to breath at the surface they drown in tuna nets. It is estimatedthat 4.8 million dolphins were killed in tuna nets from 1959 to 1972. Underpressure from animal rights activists tuna consumers will not accept tuna fromcanners that do not protect dolphins. Animal rights activists also believe thatdolphins shouldnt be in captivity for use in aquatic shows.Dolphins eat a lot of food in a day, usually about one tertiary of theirbody weight. A dolphins diet consists of mostly fish and squid. Dolphins canswim very fast, so they are able to easily catch their food. The dolphin has two hundredto 250 sharp teeth. Dolphins follow schools of fish in groups. The Pacificwh ite-sided species is estimated to travel in groups with tens of thousands ofmembers, while on the other hand bottlenose dolphins travel in groups that impart only a few members.Dolphin, like whales, breathe through a blowhole in the top of theirhead. While traveling dolphins break the surface once every two minutes. Whendolphins exhale water is sometimes thrown from the blowhole. After exhaling thedolphins inhale and disappear into the ocean. A dolphins lungs are adapted toresist the physical problems that are caused by quick changes in pressure.