The name of the dolphin comes from the Greek “Delphis” who means “Spirit of the sea”. The dolphins are above all the mammals just like us, the females nourish their small with L `assistance of udders. In fact marine mammals pass the majority of their time in L `water just like polar bears or otaries for example. In fact Cetacea choose the life in L `water. They belong to the sub-order of Odontocètes, the Cetacea with teeth, the cachalot is Odontocète. The blue whale for example formed part sub-order of Mysticètes, equipped with pennon. One can say that the cachalot is closer to the dolphin than of the whale. There are six families of Odontocètes: Physéteridés (cachalots), Ziphiidés (“whales” with nozzle), Monodontidés (the narval or the white whale), Platanistidés (the dolphins D `fresh water), Phocoenidés (porpoises) and finally Delphinidés (dolphins, orcs and globicéphales).