Evolution of Cetaceans & Dolphins

Dolphins belong to the family of cetaceans (aquatic mammals) which includes whales, dolphins and porpoises (Save The Whales, 2003). Two types of cetaceans can be identified: those which have teeth and those which have baleen. The Odontoceti include dolphins, porpoises and some species of whales such as sperm whales, beluga whales, beaked whales and narwhals. The second type are Mysticeti, or moustached whales, which includes baleen whales such as the blue, gray, humpback and minke whales. These have baleen, keratinous projections from the roof of the mouth, which allows the whales to be filter feeders.

The primitive cetaceans are believed to have evolved during the Paleocene period, around 50 million years ago, in the area which is now the Mediterranean Sea and the Arabian Gulf (Hyperion, 2003; Save the Whales, 2003). There is a lack of fossil evidence between the first cetaceans and their ancestor

Related Essays

Dolphins & the family of Cetaceans .... During this time, the cetaceans became more aquatic .... was later lost in rightwhale dolphins, the external .... Evolution favored an aquatic existence, and structures .... (613 2 )

Dolphins .... have continued adapting themselves for life on land during the course of their evolution. .... This explains why the dolphins and other cetaceans combine the .... (2777 11 )

Category: Science - E