Dolphins

Dolphin Marine Life Research Paper Throughout the years, the dolphin species has become more and more at a risk of extinction, primariliy by the demolition of their environments as well as both the unintentional and purposeful killing of dolphins due to seine fishing and harpoon dives. Dolphins first appeared on Earth some 11 million years ago during the Miocene period (“Earth Science Reference Tables”). It has been decided that dolphins first evolved from Odontocetes, large toothed wales, that lived as many as 35 million years ago (“Dolphins” The New Book of Popular Science) . Dolphins have often been categorized as the socializers of the sea, having a developed and highly complex brain, making them one of the smartest mammals on Earth (“Porpoise” Gilmore, Raymond M.). With such intilectual capability, dolphins maintain a variety of astonishing characteristics allowing them to maintain life. Perhaps the dolphins greatest achievement is its anamoty, with specific adaptations designed perfectly for their environment and life style. Every dolphin has a fusiform body, also known as a torpedo shaped figure, making them the perect candidate for fast swimming (“Dolphins” The New Book of Popular Science). They also have a number of fins useful for their lifestyle including a fluke, dorsal fin, and pectoral fins. While the fluke is used primarily for propoltion and speed, the dolphin uses its dorsal fin for stability, and its pectoral fins for direction control. With their acute eyesight, dolphins rely primarily on their sense of sound. Despite the small slits on the sides of their heads, dolphins’ hearing is managed through their lower jaw, exerting a method known as echolocation (“Dolphins” The New Book of Popular Science). Echolocation is used to locate invisible objects by a means of sound waves reflected back to the emmiter from the object (“Echolocation” M.B., Fenton). Their use of echolocation allows dolphins to engage in easy hunting of their prey, often