Evolution of Dolphins

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Approximately 95 million years ago, the ancestor of today’s dolphin, the Mesonix, roamed the earth. It was a land animal that went into the water to eat. It had front legs and back legs and was covered with hair. Plenty of the research that has been conducted shows that this is with the Artiodactyl order. It is believed that the ancestors of dolphins that we know today entered the water about 50 million years ago! Over the next 30 million years, the Mesonix evolved to be more adapted to the water than land. The front legs became pectoral flippers and the hind legs disappeared. The hair also disappeared because hair is not needed to warn an animal living in the water. The movement of the ears closer to the eyes is also part of the evolution process. After millions of years the nostrils slowly migrated from its nose to the top of the head which makes it easier to breath when swimming under water (also known as a nasal drift). Those nostrils later evolved into blowholes so that they can get to the surface of the water, take in air, and then go underwater again with ease. Also the bones of a dolphin are relatively lighter than land mammals because dolphins don’t have to carry the weight of those land animals. The head of Dolphins have changed over the years as well; it has grown larger which shows that the lower jaw emerged. It ranges to the middle ear and this helps dolphins to be able to hear as well as to use echolocation. It’s believed that during the early Miocene period, the use of echolocation was developed in the form that dolphins depend on on it today. The early dolphins were smaller and believed to have consumed small fish as well as various organisms in the water. Researchers have carefully examined the bones of the fins for dolphins. They found that they resemble the limbs of many animals on land. Dolphins have spines that move up and down opposed to

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