The Walking Whales: From Land to Water in Eight Million Years

The Walking Whales: From Land to Water in Eight Million Years

Language: English

Pages: 256

ISBN: 0520277066

Format: PDF / Kindle (mobi) / ePub

Hans Thewissen, a leading researcher in the field of whale paleontology and anatomy, gives a sweeping first-person account of the discoveries that brought to light the early fossil record of whales. As evidenced in the record, whales evolved from herbivorous forest-dwelling ancestors that resembled tiny deer to carnivorous monsters stalking lakes and rivers and to serpentlike denizens of the coast.

Thewissen reports on his discoveries in the wilds of India and Pakistan, weaving a narrative that reveals the day-to-day adventures of fossil collection, enriching it with local flavors from South Asian culture and society. The reader senses the excitement of the digs as well as the rigors faced by scientific researchers, for whom each new insight gives rise to even more questions, and for whom at times the logistics of just staying alive may trump all science.

In his search for an understanding of how modern whales live their lives, Thewissen also journeys to Japan and Alaska to study whales and wild dolphins. He finds answers to his questions about fossils by studying the anatomy of otters and porpoises and examining whale embryos under the microscope. In the book's final chapter, Thewissen argues for approaching whale evolution with the most powerful tools we have and for combining all the fields of science in pursuit of knowledge.

















it a day. We cover the site with loose rock to protect it from being trampled by herders and their flocks, and we return to the guesthouse. 46    |    Chapter 3 Ambulocetus natans The Walking Whale H-GSP 18507 femur forearm and hand hyoid foot ribs and vertebrae from the compressed chest skull lower jaw left pelvis hammer is 30 cm long sacrum right pelvis figure 18. Map of Ambulocetus excavation (locality H-GSP 9209). The fossil was in a nearly vertically oriented layer (see figure 19).

(LABIAL VIEW) Cheekside of jaw (labial) To front of jaw (anterior) LEFT UPPER MOLAR IN OCCLUSAL VIEW Artiodactyla: Indohyus Four large cusps, valleys between cusps. Four large cusps, one small cusp, valley between cusps. RR 102 RR 209 Pakicetid whale Pakicetus Only two large cusps One main cusp lost, and one small remain one small cusp lost, valleys gone. valley smaller. H-GSP 96334 H-GSP 18470 Molar morphology similar in ambulocetids Remingtonocetid whales Two large cusps remain, one

plants, and take refuge. Pakicetids were able to get around on land and in water too, but probably spent most of their time in freshwater ponds and rivers. Their anatomy reveals more aquatic adaptations than that of a tapir skeleton, and, just like tapirs, they were probably mostly waders. All pakicetid fossils from Pakistan have been found in rocks that formed in shallow ponds, in a dry climate with occasional flash floods, as discussed in chapter 3. It is likely that these cetaceans lived like

swimming in the seas surrounding New England in the pages of the Atlantic Monthly.11 Wood starts his essay by listing a number of examples of natural history phenomena that, although initially held to be untrue, were later confirmed by solid observations. Then he takes on the case of sea serpents, commenting that: It is not very difficult to be witty about traveler’s tales, and it is very easy to be sarcastic. . . . As long as an assertion cannot be proved, skepticism is triumphant. Wood

Basilosaurus show that the animal was about eighteen meters (sixty feet) long, whereas dorudontines, for instance Dorudon, were around a quarter of that (figure 9).20 Basilosaurids have been discovered in many places all over the world and were probably distributed worldwide (figure 10). figure 9. Skeletons of two fossil basilosaurid whales: the large Basilosaurus and the much smaller Dorudon. The picture of Dorudon is repeated in the upper right corner, but now at the same scale as

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