Horse

Horses are treated not as independent agents but as part of the material conditions through which people travel, work, and exchange goods. Their significance varies by context: in the Andes, a horse or mule was necessary to travel beyond Acomayo; in Somalia, pastoral life depended on herds that included horses among other animals; and in the book’s larger argument, access to animals and technology cannot alone explain why societies followed sharply different economic paths.

Transport and Unequal Access

The contrast between the Peruvian provinces of Calca and Acomayo makes transport visible as both a practical constraint and an institutional legacy. The road to Calca was surfaced, while the road to Acomayo was badly deteriorated; travel beyond Acomayo required a horse or mule. Although the provinces shared high-mountain settings and Quechua-speaking populations descended from the Incas, Acomayo was much poorer. Its residents consumed about one-third less than people in Calca, and their crops were grown for subsistence rather than sold for money in markets. The book connects this divide to colonial institutions, not to any inherent difference in the people or landscape. Acomayo lay within the catchment area of the Potosí mita, the system of forced labor associated with Spanish colonial rule; Calca did not. The transport difficulty is therefore part of a broader contrast in economic opportunity whose roots the book traces to institutions that organized labor and exchange.

Animals, Technology, and Historical Explanation

In discussing Jared Diamond’s account of intercontinental inequality, the book notes the importance of domesticated plant and animal species to the development of farming. Earlier agriculture, it argues in its summary of Diamond’s thesis, supported population growth, specialization, trade, urbanization, and political development. The Spanish also possessed animals and technologies unavailable to the Incas, including horses. But the book cautions that this advantage cannot explain modern income inequality: the income gap between Spain and Peru widened dramatically after the conquest, even though Peru had been exposed to those species and technologies. The decisive distinction, in this account, is not simply whether a society encountered horses or other useful technologies, but whether institutions supported their adoption and the spread of innovation. Spain adopted steam power, railroads, electricity, mechanization, and factory production, while Peru did so slowly and imperfectly. The persistence of that technological gap, rather than any fixed difference in agricultural potential or access to domesticated species, helps explain why incomes diverged.

Herds and Customary Obligations in Somalia

The book’s discussion of Somalia places horses within a pastoral economy organized around clan families and their herds. Pastoral groups migrated with goats, sheep, and camels, while disputes over scarce resources—especially water and good grazing land—could lead to conflict and raids. The passage names horses as part of the wider animal world considered in its discussion of transport and technology, but it does not identify them as a distinctive basis of Somali social organization; that role belongs more directly to herds, grazing, and the customary obligations governing relations between groups. In the customary system described, diya-paying groups collected and paid blood wealth to compensate for harm to their members. The rules were set out in a heer, which specified rights, duties, and obligations. The book’s examples show how collective responsibility operated in practice: compensation could be paid in camels, and an agreement did not necessarily end disputes permanently. This social order depended on negotiated obligations and the threat of collective retaliation rather than a centralized authority able to enforce law and property rights.

The Limits of the Evidence

Across these examples, horses matter most as one element in a larger account of access, mobility, and technological change. They could be indispensable for reaching isolated places, and they belonged to the animal endowments invoked in explanations of agricultural development. Yet the book resists treating animals as a sufficient explanation for prosperity. The contrasting fortunes of Calca and Acomayo, the widening income gap between Spain and Peru, and Somalia’s difficulties in adopting new technologies are presented as outcomes shaped by institutions: who controlled labor and exchange, whether transport and innovation could be supported, and whether political authority could establish order.