Guns, Germs, and Steel

The first chapter presents a whirlwind account of human evolution. 11,000 BCE is a useful starting point for discussing how the world’s continents developed. It was at this point that village life began in some areas and the Americas started to be peopled; geologists term this the Recent Era. However, Diamond’s purpose in this chapter is to establish whether some continents already had a head start.

Human beings trace back to hominids that lived in Africa; hence, we can ascertain that human evolution began on this continent too. Human history commenced around seven million years ago when these hominids split into three populations, a third of which evolved into humans. Diamond charts the stages of this evolutionary process, explaining that, by around 2.5 million years ago, these hominids had achieved an upright posture and increased in body size and brain size. These proto-humans are categorized as Homo erectus, but their brain size was still barely half of our own. Even so, they were the first human ancestors to spread beyond Africa, with fossils having been found on the Asian island of Java.

Fossils also demonstrate that, by around half a million years ago, the human skull had developed to the extent that it can be classified as our species: Homo sapiens. This stage of humanity was still nowhere near as advanced as our own, though, as demonstrated by the scarcity and crudeness of the artifacts they left behind.

After this point, skeletal details diverged between those continents that had become populated, which did not yet include Australia and the Americas, as access to these continents would have required boat-building skills. Diamond explains that between 130,000 and 40,000 years ago, Europe and Western Asia were populated by Neanderthals, who had slightly larger brains than ours, but whose stone tools were still relatively crude. As for Africa, the skeletons discovered there during this period are more akin to those of modern humans than those of the Neanderthals. Again, though, their stone tools remained primitive and their hunting skills unimpressive. We can therefore conclude that both the Neanderthals and their African counterparts were not yet fully human.

Human history finally took off around 50,000 years ago, with the first signs of advancement coming from East African sites featuring standardized stone tools and preserved jewelry. The Near East and southeast Europe followed soon after, and southwestern Europe subsequently produced numerous artifacts associated with the skeletons of people termed Cro-Magnons. Archaeological evidence becomes abundant from this point on and provides evidence of human development. These artifacts include more advanced tools and weapons, and the remains of houses, clothes, and jewelry. The cave paintings, statues, and musical instruments these people left behind also indicate aesthetic progress.

Some dramatic change took place between 100,000 and 50,000 years ago, though its cause has not been established. Diamond has argued in one of his previous books that the perfection of the voice box was responsible for this shift, because the voice box allowed the development of modern language, upon which the exercise of human creativity depends. Other scholars, meanwhile, have suggested that a change in brain organization occurred around that time and made modern language possible.

The geographical site of this shift also remains uncertain. Did it take place primarily in one geographical area, whose inhabitants then spread to other parts of the world? Or did it take place simultaneously within different regions? Modern-looking human skulls found in Africa, which date from 100,000 years ago, seem to support the former view. However, skulls found in Indonesia and China suggest parallel evolution.

This issue therefore remains unresolved, but Diamond suggests that the strongest evidence for the former view—that is, a localized origin of modern humans, followed by migration to other areas—can be found in Europe. The Cro-Magnons entered Europe around 40,000 years ago and somehow used their superior intellect and technology to kill or displace the Neanderthals.

The onset of major human advancement, the Great Leap, involved geographical expansion to Australia and New Guinea. This important event attests to humans’ ability to build watercraft. However, another major effect of human inhabitation was the mass extinction of Australia and New Guinea’s native animals. Mostly likely, humans either hunted by or indirectly killed these animals. In Africa and Eurasia, animals had co-evolved with proto-humans and therefore learned to fear humans and their hunting skills. Animals in Australia/New Guinea, by contrast, confronted modern, advanced humans without any evolutionary preparation.

Ultimately, no sufficient evidence has established the cause of the animals’ extinction, and the debate goes on. Diamond believes that humans most likely killed these animals but, in any case, Australia and New Guinea were left without a single native domestic animal.

In addition to Australia and New Guinea, this Great Leap also peopled the coldest parts of Eurasia. Neanderthals had lived in glacial times and had acclimatized to the cold but they had not spread further north than Germany and Kiev. This makes sense, as they would not have had sufficient tools to ensure survival in a colder climate. Growing more advanced, however, human beings expanded into Siberia around 20,000 years ago.

Now, human beings occupied three of the five habitable continents, with only North and South America remaining uninhabited. Settlement had originally been impossible in these areas because it required either the ability to build boats or the occupation of Siberia, which would enable access via the Bering land bridge. It is not clear when the Americas were first colonized, but the continents’ oldest known human remains, dating from 12,000 BCE, were found in Alaska. Other remains were later found in the United States and Mexico, dating from 11,000 BCE. These latter sites are known as “Clovis” sites; hundreds of similar settlements are now known to have existed throughout the United States before expanding into South America.

As with Australia and New Guinea, the Americas were full of big mammals that became extinct—in this case, around 11,000 BCE. Again, these animals may have proven easy targets since they had never seen humans before. Another theory claims they may have become extinct due to climate changes at the end of the last Ice Age. However, Diamond points to a problem with this theory: Since America’s big animals had already survived 22 previous Ice Ages, there is no reason to think that they couldn’t have lasted through this one.

Whatever the case, the five habitable continents were now occupied. What impact, if any, did these differing rates of settlement have on subsequent human history? An explorer transported back to 11,000 BCE could not predict on which continent human development would progress most quickly. However, hindsight shows that Eurasia was that continent. The rest of the book will explore why.

The individual islands that make up Polynesia have developed in substantially different ways. A conflict emerged between the Maori and the Moriori peoples, despite their shared origins.

There are thousands of islands scattered over the Pacific Ocean beyond New Guinea, some of which were settled from around 1200 BCE onwards. Despite the shared origin of the settlers, these island societies developed in a diverse manner because of their individual environments. Diamond explains that there are at least six variables that need to be considered when analyzing the effect that environment has on social development: climate, geology, marine resources, terrain fragmentation, and isolation. Climate, for instance, can foster a community that is able to depend on agriculture or one that must focus on hunting and gathering.

The Maori and Moriori developed differently because of their different environments: New Zealand and the Chatham Islands, respectively. The Moriori hailed from New Zealand, but colonized the Chathams and had to alter their lifestyle accordingly, developing into “a small, unwarlike population with simple technology and weapons, and without strong leadership or organization” (56). By contrast, the Maori who remained in New Zealand grew in number; they formed locally dense populations and engaged in continual warfare. They also developed various tools for the purposes of fighting, growing crops, and producing art.

Rather than living in a peaceful state of coexistence, when the Maori arrived in the Chatham Islands in 1835, they killed and enslaved the Moriori. As the Moriori were ill equipped and accustomed to solving conflict peacefully, they failed to establish the organized resistance that may have foiled their attackers, highlighting a contrast between the simplest, egalitarian societies and those that had become more socially diverse.

As Diamond emphasizes, the Moriori and Maori were both Polynesian peoples and had diverged from the same origin within a relatively short space of time. Diamond uses this as a model for understanding differing developments on a broader level, with environment having the capacity to “affect economy, technology, political organization, and fighting skills within a short time” (57).

As in the previous chapter, Diamond uses a specific example to demonstrate a wider trend. In this case, he details the defeat of the Inca emperor Atahuallpa and his army by the Spanish conquistador Francisco Pizarro in 1532. Despite the Inca army’s superior numbers, the Spaniards possessed more advanced weaponry, fought on horseback, and were the product of a literate culture. The Incan army, meanwhile, had no idea of how advanced the Spanish army was, having been ill informed. Also, the existence of European maritime technology enabled the Spanish to expand overseas, whereas the Inca had no such means of expansion.

Another relevant factor is that, in the run-up to this conflict, the Incas had been left divided and vulnerable by civil war. This civil war broke out when the Incan emperor, Huayna Capac, along with most of his court and his immediate heir, died in a smallpox epidemic brought to South America by Spanish settlers. These deaths instigated a contest for the throne between Atahuallpa and his half-brother, thus fostering division. If the epidemic had not occurred, the Spanish would have faced a united force.

The issues that came into play here were also deciding factors in other instances of conflict between Europeans and Native Americans. Technological imbalances often helped to decide the outcome of such clashes. Likewise, the transmission of diseases from people with considerable immunity to those lacking immunity constitutes another key factor in world history. However, disease did not always pave the way for European expansion; on the contrary, diseases found in areas such as tropical Africa, India, New Guinea, and Southeast Asia often hindered would-be colonizers.

Diamond points to this clash between the Spanish and the Incas as an instance of the Old World colliding with the New World—a conflict that began in CE 1492 when Christopher Columbus discovered the Caribbean islands inhabited by Native Americans. However, there remains the question of why the Europeans possessed more immediate advantages compared to those of the New World.