The Walking Whales
by J.G.M. "Hans" Thewissen
University of California Press
I've read a lot of good books lately on marine life and its prehistory, but Thewissen's stands out. The veteran paleontologist, a specialist in whale ancestry, simply does everything right in this slender but fact-packed volume.
His discussions of the science are clear and well-illustrated, and his adventures as a paleontologist in India and Pakistan present the risks, the tedium, and the thrill of discovery. Science is, after all, a human story. One crucial discovery was made by accident when a bone was broken in the lab, and I found that very interesting. Despite all our modern tools, science still depends partly on luck.
The author leads us, with very good explanations, through the complicated business of how evolution transformed land animals into aquatic ones. There were more whales than anyone suspected when the author began his own excavations and searches. Just twenty years or so ago, whales were often pointed to by young-Earth creationists as an example of seemingly huge change in a relatively short time but with no transitional forms. Now we know that whales are not only fascinating creatures, but offer one of the most complete evolutionary records of any modern group, with many transitional forms we can use to trace the development of particular traits. (The author makes a humorous but insightful comparison to whale evolution by asking readers to imagine the Batmobile being given to a group of engineers with orders to use its parts to build the Beatles' Yellow Submarine.) I wanted a little more explanation of how the diet developed (the whales' closest relatives on land are, after all, vegetarians), but I was fascinated to learn that teeth are in fact present in fetal baleen whales, and traces sometimes show up in adults.
Overall, this book is everything I could have hoped it was. Excellent job!