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The skulls of two pakicetid whales (Ichthyolestes on the left, Pakicetus on the right), flank the skull of a modern coyote. |
Pakicetids were the first cetaceans, and they are more primitive than other whales in most respects. In fact, they did not look like whales at all, and did not live in the sea. Instead they lived on land, and may have fed while wading in shallow streams. Fossils of pakicetids are only found in Pakistan and Northwestern India, and it is likely that cetaceans originated there.
Although pakicetids were land mammals, it is clear that they are related to
whales and dolphins based on a number of specializations of the ear, relating
to hearing.
Genera of Pakicetids
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Photograph (above) of bones of Pakicetus (large animal) and Ichthyolestes (small animal), and a line drawing of the same skeletons. The sledge hammer indicates the size of the skeletons, and shows that Pakicetus was approximately as large as a wolf, and Ichthyolestes is as large as a fox. The lower figure is published (Thewissen, Williams, Roe, and Hussain, 2001, Nature Vol. 412, September 20, 2001) and copyrighted and can only be used by permission of the publisher.
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| A reconstruction of Pakicetus, based on the skeletons above. This reconstruction can be used freely, but this statement has to be added to its caption: Illustration by Carl Buell, and taken from http://www.neoucom.edu/Depts/Anat/Pakicetid.html. |  |
| A high-resolution image of these images can be found at URL: http://www.neoucom.edu/Depts/Anat/publ.html | |
All pictures on Dr. Thewissen's pages are public access, although the source must be identified in publication.
Ambulocetidae
| Basilosaurids and
Dorudontids | Bibliography | Hearing
| India |
Locomotion | Mysticetes
| Odontocetes | Osmoregulation
| Pakicetidae |
Pakistan | Protocetidae
| Remingtonocetidae | Whale
| Whale Origins!