Paleoanthropologists are all too often absorbed with “who” questions: What hominin species made the Oldowan? Who is responsible for the Châtelperronian? Or “who had sexual intercourse with whom in the Ice Age?” (p. xv). In this thoughtful, fast-paced, and frequently humorous treatise, Paleolithic archaeologist John J. Shea makes the persuasive argument that we should instead be asking much more interesting “how” questions, such as the following: How did humans traverse landscapes teeming with obstacles like mountains, deserts, rivers, and seas? How did they make and use fire or build shelters? Or, more essentially, how did prehistoric humans solve the multiple survival problems they would have encountered as they expanded into new habitats? Our own existence is, of course, proof that our ancestors did successfully solve myriad problems as they spread across the globe.
In addressing “how” questions, Shea draws from multiple lines of evidence: the archaeological record, experimental archaeology, ethnography/ethnoarchaeology, “bushcraft” and wilderness survival literatures, and nonhuman primate ethology. He points out the advantages and pitfalls of these approaches before turning his attention to six major survival challenges faced everywhere by prehistoric humans: first aid/medication, thermoregulation, hydration, nutrition, transportation, and communication.
Shea's thesis is that Homo sapiens became “unstoppable,” or acquired near-immunity from extinction, through a unique integration of a suite of “ancestral survival skills” shared with at least some of our ancestors and that they often used in a habitat-specific way. These include powerful precision gripping, predictive hallucination (i.e., imagining potential future events and how to deal with or avoid them), endurance bipedalism, language/quantal speech, hyperprosociality, and technical skills such as fire making and cordage manufacture.
This data-rich, theoretically sound book is organized into thematic sections. Chapters 1–3 serve as a primer on human evolution, prehistory, paleogenetics, the mechanics of paleoanthropological fieldwork, and an epistemological examination on how we know what we think we know about the archaeological and paleontological records. Little here is new to the specialist, but Shea's accessible work is written to appeal to a much broader audience.
In Chapter 4 he lays out the book's thesis, introducing our ancestral survival skills and the challenges to survival our ancestors faced. The “meat” of the book, however, is found in Chapters 5–10; they provide a continent-by-continent case study comparing how Pleistocene Homo sapiens (and Neanderthals in Chapter 8) fared relative to their presumed ancestors (Homo heidelbergensis, according to Shea). Here we learn about early African Homo sapiens and follow humanity's expansion into western Asia, south Asia, and Australasia and then on into northern Eurasia and the Americas. Chapters 11 and 12 discuss the Holocene emergence of food production and describe the amazing oceanic migrations that Polynesians took about 1,000 years ago across the Pacific as far as the South American coast. Chapter 13 looks into the future to ask what are the most likely existential threats that humans face in both the near and long term, and Chapter 14 ties the book's arguments together in a tidy conclusion. For the nonspecialist, Shea provides a handy glossary (pp. 311–319).
There is a lot to love in this smart, fun book. One helpful resource is that each of the continental chapters includes a table of important sites, their absolute dates, and comments on their significance. The book's maps and artifact illustrations are welcome visual aids, although I do not share Shea's enthusiasm for the Mercator projection. Perhaps my favorite chapter is “Neanderthal Country,” in which Shea argues that Neanderthals lived in places where multiple ecotones came together, allowing a focus on different foods at different elevations and habitats during different times of the year. Neanderthals, he says, likely had larger home ranges than Homo sapiens but dispersed less and, as such, relied on local resources. He claims that Neanderthals neither added to nor subtracted from the survival skills they inherited from their Homo heidelbergensis ancestors.
I have minor quibbles here and there—Shea doubts the existence of Neanderthal parietal art (p. 191), his primate taxonomy (p. 50) includes some errors, and his cranial drawings are not as good as his artifact illustrations. Yet this delightful book will have great appeal for specialist and layperson alike. Shea's wry humor shines throughout—for example, “Many archaeologists think prismatic blades were more difficult to make than shorter flakes and therefore especially informative about earlier hominin intelligence and skill. As with so much of what archaeologists believe about stone tools, little or no evidence supports this hypothesis” (p. 40).
The Unstoppable Species is a must-read for anyone interested in how we came to be the cosmopolitan species we are today.
