Subject: Fin whales and evolution

Jennifer D. Philips (jphilips@soest.hawaii.edu)
Thu, 29 Oct 1998 14:30:41 -1000



Hello,
=A0=A0=A0 I am working on a report about fin whales.=A0 I am trying to find information on the evolution of whales.=A0 What is their family tree?=A0 Any help would be appreciated.
=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0= =A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0 sincerely,
=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0= =A0=A0=A0=A0=A0=A0=A0=A0=A0=A0 Robin Sischo

Robin -

The first recognizable cetaceans lived in the seas about 50 million years ago.  They are called the Archaeocetes, members of the suborder Archaeoceti.  They are thought to have evolved from a group of animals of the order Condylarthra, which is also the ancestor of modern even-toed ungulates (antelope, camels, etc).  So, 50 million years ago, some ancestor of cows decided that there was a whole entire niche to exploit in the warm marshy Tethys Sea, and never turned back.  The body elongated, the limbs became reduced, the snout became longer, the nostrils shifted backwards, and structures developed making life in the sea possible.  Eventually, by the mid-Oligocene 25-30 million years ago, toothed whales and baleen whales separated:  the teeth of some of the species which had developed from the initial Archaeocetes were replaced by long rows of kertin plates.  These plates evolved into the baleen seen today in modern baleen whales, including the fin whale.  The rorquals, which is the group of whales including the fin whale (the Balaenopterids) is thought to have arisen during the Late Miocene 5-15 million years ago. 

For more info, I would suggest looking into a couple resources such as:
A 1995 issue of Science had a very concise account of whale evolution, called"What is a Whale?".

The National Geographic also had an issue containing a great article on the current understanding of whale evolution (though I'm not sure of the date, sorry!)

Hope this has helped to answer your question. Write again anytime.

Aloha -
Jen Philips



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Jennifer D. Philips     
jphilips@soest.hawaii.edu

Marine Mammal Research Program
HIMB, University of Hawaii at Manoa
PO Box 1106      = ;  
Kailua, HI  96734
voice:  (808) 247-5063
fax: (808) 247-5831
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