At repeated intervals throughout Earth’s history, there’s been more energy pouring in from the sun during the West African monsoon season, and during those times-known as African Humid Periods-much more rain comes down over north Africa. These fluctuations are caused by slight wobbles in the tilt of the Earth’s orbital axis, which in turn changes the angle at which solar radiation penetrates the atmosphere. The Sahara has long been subject to periodic bouts of humidity and aridity. In a new study in the journal Frontiers in Earth Science, Wright set out to argue that humans could be the answer to a question that has plagued archaeologists and paleoecologists for years. So where did all that water go?Īrchaeologist David Wright has an idea: Maybe humans and their goats tipped the balance, kick-starting this dramatic ecological transformation. The now-dessicated northern strip of Africa was once green and alive, pocked with lakes, rivers, grasslands and even forests. But 11,000 years ago, what we know today as the world’s largest hot desert would’ve been unrecognizable. The goal of the Princeton Legacy Library is to vastly increase access to the rich scholarly heritage found in the thousands of books published by Princeton University Press since its founding in 1905.When most people imagine an archetypal desert landscape-with its relentless sun, rippling sand and hidden oases-they often picture the Sahara. These editions preserve the original texts of these important books while presenting them in durable paperback and hardcover editions. ThePrinceton Legacy Libraryuses the latest print-on-demand technology to again make available previously out-of-print books from the distinguished backlist of Princeton University Press. Whereas this rich detail holds many implications for natural scientists, the colorful way it comes to life makes for a compelling book bound to entertain and educate all readers.

At the same time, clear-cut personalities emerge from Kummer's account, drawing us into the life stories and power struggles of individual baboons. We learn, for example, of the Hamadryas' respect for possession that protects family structure and of the cohesion among family leaders that lessens the threat of battle. Much like the human nomads who cope with the harsh demands of the desert environment, the Hamadryas maintain a society that is strict and patriarchal in its details but multilayered and flexible in its largest units. Winding his way through cliffs and stubble, Kummer records the baboons' social life, from the development of pair relationships to the way an entire group decides where to march each day. His scientific account of this period reads like a travel memoir as he describes his encounters with the Hamadryas and the people with whom they share the desert. In the 1960s, Kummer, after conflicts with nomadic warriors, managed to track down these elusive baboons near the Danakil Desert, and then followed them from dawn to dusk on their treks from one feeding place to another.

Back then, Hamadryas were thought to be incarnates of Thoth, the god of wisdom today they are considered to have one of the most highly structured social systems among primates, very close, in some respects, to that of humans. With their furry white mantles and gleaming red hindquarters, the Hamadryas appear frequently in the art of the ancient Egyptians-who may have interpreted the baboons' early morning grooming rituals as sun-worshiping rites. Just as Jane Goodall and Dian Fossey introduced readers to the fascinating lives of chimpanzees and gorillas, Kummer brings us face to face with the Hamadryas baboon. In a tale that begins at a zoo in Zurich and takes us across the deserts of Ethiopia to the Asir Mountains in Saudi Arabia, Hans Kummer recreates the adventure and intellectual thrill of the early days of field research on primates.

A tale in the desert ecology skill