If you pick up this book by Peter Ward thinking it will be about the Gorgons, the lion-sized apex predators of the last years of the Permian age, you will be disappointed. The beasts themselves play only a minor role in the story, and if you took everything the book says about them it would probably fill only a page or two. Instead, this book is about the search for the cause of their extinction, the great dying-off of 250 million years ago, when over 90% of land and sea creatures went extinct, the closest life ever came to being wiped out.
For decades it was believed that the extinction event was caused by gradual changes in the climate, along with volcanic activity, and extending for millions of years. After the discovery of the impact event that ended the age of dinosaurs 66 million years ago, there was new interest in finding out whether a similar catastrophe could have ended the Permian.
This book describes Ward’s excavations in the Karoo, a harsh, arid region of South Africa, subject to extremes of heat and cold. Its rocks straddle the Permian-Cretaceous boundary, and are rich in fossils from both sides of the boundary. He visited it half a dozen times in the 80s and 90s, collecting fossils and studying the layers of rock. He describes the processes by which paleontologists gather evidence to build theories, and anyone who thinks that it is glamorous work will be disabused of that notion. It was endless drudgery under terrible conditions in a very hostile climate. At one point he visits with an expert in geomagnetism, tracking the age of rocks based on their magnetic alignment when they solidified. They drilled two hundred fifty cores in the rock, averaging about twenty a day, and it was dirty, tedious, exhausting work in brutal heat.
For someone who had been to the Karoo and knew its dangers, the author had an odd habit of going out unprepared. At one point he is there in the winter and gets caught in a furious snowstorm, but had forgotten to bring a jacket and had only two sweaters. Another time, in the hottest days of the summer, he left half his water behind because it was heavy, and suffered greatly in the scorching heat.
The book sometimes drifts away from its main subject, as if the author wanted to show that he is not just a scientist, but a responsible social critic as well. He made his first visits to South Africa when it was still under apartheid, and notes that for whites it was safe and orderly but oppressive. He returns after black majority rule was established, and saw the country slipping into increasing lawlessness and chaos. His comments are interesting, but South Africa’s struggles in the post-apartheid era are well known, and the book adds little to the reader’s understanding of them. Only one non-white companion on his trips to the Karoo is described in any detail.
There is still no generally accepted explanation for the great extinction, and arguments are made for both catastrophism and gradualism. Both sides have evidence to support their position, but none of it is conclusive. No one has found an impact crater, and the the affiliated geological evidence is subject to multiple interpretations.
The author’s position, when this book was published in 2004, was that sea levels fell, exposing vast beds of organic material which began to oxidize, pulling so much oxygen out of the atmosphere that it affected the ability of animals to breathe. At the same time, enormous, long lasting volcanic eruptions pushed carbon dioxide into the atmosphere, causing further respiratory distress. Ultimately, he believes, the animals slowly suffocated. It might have taken thousands or tens of thousands of years but in geological time that would still be considered a rapidly unfolding event. What survived seemed to be creatures with large lung capacity, such as cynodonts, the ancestors of mammals. He speculates that they could have originally evolved at high altitude, developing large lungs to compensate for the thin air, which enabled their descendants to survive until the atmosphere turned favorable for life again. For millions of years after the Permian-Cretaceous boundary event cynodonts are one of the few fossils found in abundance.
This book is more about the paleontology grind than the animals of the time or their lives. For those with an interest in the processes involved in painstakingly gathering evidence and then turning it into theories, papers, grants (and jobs), there are interesting details here. For those who were looking for a window into another age of the earth, there are more focused books to choose from.