Os Cetáceos (baleias e golfinhos) são um dos 5 grupos de mamíferos marinhos, juntamente com os pinípedes (focas, otárias e morsas), os sirénios (manatins e dugongos), as lontras e os ursos polares. Evidências moleculares e fósseis sugerem que baleias e golfinhos incluem-se dentro dos artiodáctilos, o grupo de mamíferos com cascos em número par, e.g. porcos, vacas e hipopótamos.ABSTRACT: Cetaceans (whales, dolphins, and porpoises) are one of the 5 groups of marine mammals, which also include pinnipeds (seals, sea lions, and walruses), sirenians (dugongs and manatees), sea otters, and polar bears. Fossil and molecular evidence suggests that whales and dolphins are a group within the artiodactyls (the group of eventoed, hoofed mammals that includes pigs, cattle and hippopotamus).N/
