By Amelia Meyer
Over the millennia, a number of animal species have lived and, sadly, died off. This has been due to climatic changes, human interference and, sometimes, to mysterious circumstances. Cetaceans and, more specifically, whales are no exceptions. The group of extinct, primitive whales are classified in the suborder Archaeoceti. Today, we know of around 140 cetacean species that are already extinct. Studying these and learning more about them provides an interesting foundation on which to understand the whales that are still in existence. It also explains much about the condition of the earth and its waters millennia back.