What makes an ape an ape?
What makes a human a human?
What features originally united us?
The answers lie deep in the past, some 18 million years ago, when the last common ancestor of humans and apes was a creature known as Proconsul. By modern standards neither an ape nor a hominid, Proconsul tells us where we all began.
Part adventure story and part cutting-edge science, THE APE IN THE TREE: An Intellectual and Natural History of Proconsul, published by Harvard University Press, provides a privileged insiders' view of how fossils are found and how they are interpreted. Alan Walker, a distinguished paleontologist, has been intimately associated with Proconsul fossils since his graduate-school days; his wife Pat Shipman, is an anthropologist and celebrated science writer. Together they have crafted a compelling and accessible narrative that educates and fascinates. Both authors are faculty members at Penn State University, where Walker is Distinguished Professor of Anthropology and Biology and Shipman is Adjunct Professor of Anthropology.
In the first part of the twentieth century, fossil teeth, jaws, a spectacular skull of Proconsul found by Mary Leakey, and a stunning partial skeleton shaped anthropologists' ideas of our distant past. In 1980, when Walker happened to recognize some misidentified bones from the well-known partial skeleton in the National Museum of Kenya in Nairobi, the chance find set him on his own quest to unravel Proconsul's secrets.
He began by "excavating" in the museum, turning up still more pieces of the famous skeleton in the collections. Then he moved on to field work, leading an expedition to remote Rusinga and Mfangano Islands in Lake Victoria, where early finds had been made.
Walker and his field crew struggled against extreme weather, wildlife, and locals who misunderstood their aims, yet they managed to relocate the old Proconsul sites. To their astonishment, they found that the original skeleton site preserved the contents of an ancient hollow tree: skeletons of carnivore's prey that had been carried to its lair. At least one Proconsul, then, was found in a tree. The team also found incredibly rich new sites, returning triumphantly to Nairobi with an unprecedented ten new partial skeletons of Proconsul. As a bonus, they collected hundreds of specimens of contemporary species -- rhinos, pigs, carnivores, rodents, hyraxes, reptiles, plants, and trees. They had gathered fossil evidence of almost every aspect of the Miocene community in which Proconsul lived.
Half the challenge was finding the fossils; the other was understanding them. To analyze this superb collection of fossil material, Walker put together a collaborative team that used both traditional techniques and innovative high-tech methods in laboratories in England and the U.S. Together they investigated Proconsul's geographic and temporal distribution, studied its anatomy, biology, growth, diet, and way of moving around the world, and compared this information to what is known of other similar species from the Miocene of Africa.
As Walker sums it up, "I know how they grew from infancy to adulthood . . . I also know an amazing amount about their habitats and habits: the things they ate and the things that ate them . . . I know that there was an evolutionary blossoming, what is technically called an adaptive radiation, of these strangely familiar creatures . . . Proconsul is neither ape nor human, but something else: something ancestral, extinct, and fascinating. In more ways than one, Proconsul is truly the ape in the tree, the ape in our tree."
Alan Walker is a renowned paleontologist, a Fellow of the Royal Society, and a member of the National Academy of Sciences. He is also the recipient of a MacArthur "genius" award. Pat Shipman is an award-winning science writer and anthropologist; she is a Fellow of the Royal Geographic Society and the American Association for the Advancement of Science.
The Ape in the Tree
An Intellectual and Natural History of Proconsul
By Alan Walker and Pat Shipman
Harvard University Press
Available 30 April 2005
288 Pages; ISBN 0-674-01675-0
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