Back تطور الحيتانيات Arabic Evolució dels cetacis Catalan پەرەسەندنی نەھەنگەکان CKB Evolution of cetaceans English Evolución de los cetáceos Spanish فرگشت آببازسانان Persian Valaiden evoluutio Finnish Histoire évolutive des cétacés French אבולוציה של לווייתנאים HE A cetek evolúciója Hungarian
The Cetaceans (whales, dolphins and porpoises) are mammalian marine descendants of land mammals. Their terrestrial origins are indicated by:
- Their need to breathe air from the surface;
- The bones of their fins, which resemble the limbs of land mammals
- The vertical movement of their spines, characteristic more of a running mammal than of the horizontal movement of fish.
The question of how land animals evolved into ocean-going leviathans was a mystery until recent discoveries in Pakistan revealed several stages in the transition of cetaceans from land to sea.
- ↑ Thewissen J.G M. & Williams E.M. (2002). "The early radiations of Cetacea (Mammalia): evolutionary pattern and developmental correlations". Annual Review of Ecology and Systematics. 33 (1): 73–90. doi:10.1146/annurev.ecolsys.33.020602.095426.