The Demographic Collapse of the Andean Population

The demographic collapse of the Andean population is the single most important fact about the Spanish conquest and its aftermath. The indigenous population of the Inca Empire in 1520 has been estimated at between ten and twelve million people. By 1620, after a century of European rule, the indigenous population of the central Andes had fallen to perhaps 600,000 to 1.3 million, depending on the region. The proximate cause of the collapse was the introduction, by the Spanish, of a series of Eurasian epidemic diseases — smallpox, measles, influenza, typhus, and diphtheria — against which the Andean population had no acquired immunity. A second important cause was the social disruption caused by war, displacement, and the destruction of the Inca system of labor extraction. The demographic collapse had profound consequences for every aspect of Andean life, and it remains the most important demographic fact about the modern Andean countries.

Estimates of the pre-conquest population

The Inca census and its limits

The pre-conquest population of the Inca Empire has been the subject of an extensive historical and archaeological literature, and the estimates vary widely. The Spanish chroniclers, including Pedro Cieza de León and Bernabé Cobo, reported that the Inca kept detailed records of the population in the quipus — the knotted-cord accounting devices that were used by the Inca state. The Spanish, however, were unable to read the quipus, and they relied on indigenous informants for the population figures. The figures that the Spanish recorded — for example, the figure of 16 million that Cieza de León reported for the empire as a whole — are now considered to be exaggerated, and modern estimates place the pre-conquest population of the Inca Empire at between ten and twelve million people.

The modern estimates of the pre-conquest population are based on a combination of archaeological evidence, colonial records, and the analysis of the quipus. The most reliable modern estimate, by the historian Noble David Cook, places the pre-conquest population of central Peru at about 9.5 million, and the pre-conquest population of the empire as a whole at about 10 to 12 million. The estimates for the highland populations are higher than the estimates for the coastal and lowland populations, and the highland basins of Peru and Bolivia were among the most densely populated regions in the pre-Columbian Americas.

The population of the major regions

The population of the Inca Empire was distributed unevenly across the major regions. The central highlands of Peru, including the basins of Cusco, the Mantaro valley, and the Callejón de Huaylas, supported perhaps 4 to 5 million people. The northern highlands of Ecuador, including the basins of Quito, Cuenca, and Ibarra, supported perhaps 2 to 3 million people. The southern highlands of Peru and Bolivia, including the basin of Lake Titicaca, supported perhaps 2 to 3 million people. The coastal valleys of Peru supported perhaps 1 to 2 million people, and the eastern lowlands supported a smaller but substantial population of perhaps 0.5 to 1 million people.

The population of the Inca Empire was, in effect, concentrated in the highland basins, where the climate was favorable for agriculture and where the Inca road system connected the major population centers. The coastal valleys, although they were less densely populated, were economically important because of their agricultural productivity and their access to the sea. The eastern lowlands, although they were sparsely populated, were important because of their role as a source of tropical products and as a refuge for peoples who had been displaced from the highlands by Inca expansion.

The course of the demographic collapse

The first smallpox epidemic, 1524–1527

The demographic collapse began with the first smallpox epidemic of 1524–1527, which spread from the Caribbean coast into the interior of the Andes along the Qhapaq Ñan. The epidemic killed the Sapa Inca Huayna Capac and his designated heir, set off the civil war of succession between Huáscar and Atahualpa, and reduced the population of the central Andes by a substantial proportion. The mortality from the first epidemic is estimated to have been in the range of 25 to 50 percent of the affected populations, and the total number of deaths in the central Andes has been estimated at 2 to 4 million people.

The first epidemic, although it was severe, was only the beginning of the demographic collapse. A second epidemic, also of smallpox, reached Peru in 1529 or 1530, and a third epidemic, of measles, arrived in 1531 or 1532. The second and third epidemics were less severe than the first, but they added to the demographic burden of the indigenous population, and they coincided with the Spanish conquest and the early years of the colonial regime. A series of further epidemics — of influenza in 1558, of measles in 1589, of smallpox in 1585 and again in 1595, of typhus in 1585, and of diphtheria in 1614 — followed over the next century.

The cumulative effect

The cumulative effect of the European epidemic diseases was catastrophic. The historian Noble David Cook has estimated that the total indigenous population of central Peru fell from about 9.5 million in 1520 to about 1.3 million in 1620, a loss of about 86 percent. The figures for the central highlands of Bolivia are of similar magnitude, and the figures for the northern highlands of Ecuador are somewhat lower but still in the range of 70 to 80 percent. The demographic collapse was, in effect, a catastrophe that was unprecedented in the history of the Americas, and it has shaped the demographic structure of the Andean countries to the present day.

The demographic collapse was not uniform across the Andean regions. The highland populations, which were more concentrated and more connected to the road system, were more severely affected than the coastal and lowland populations. The populations of the central highlands of Peru, including the basins of Cusco, the Mantaro valley, and the Callejón de Huaylas, were particularly hard hit, with mortality rates of perhaps 90 percent or more. The populations of the northern highlands of Ecuador, including the basins of Quito, Cuenca, and Ibarra, were somewhat less severely affected, with mortality rates of perhaps 70 to 80 percent. The populations of the eastern lowlands, which were less connected to the road system, were less severely affected, with mortality rates of perhaps 50 to 70 percent.

Causes of the demographic collapse

Epidemic disease

The proximate cause of the demographic collapse was the introduction of European epidemic diseases. The most important of these diseases were smallpox, which arrived in 1524 and was responsible for the largest single wave of mortality; measles, which arrived in 1531 and caused further waves of mortality; influenza, which arrived in 1558 and caused severe mortality in the central highlands; typhus, which arrived in 1585 and caused severe mortality in the southern highlands; and diphtheria, which arrived in 1614 and caused severe mortality in the central highlands. The cumulative mortality from these diseases has been estimated at about 86 percent of the central Andean population between 1520 and 1620.

The Andean population was particularly vulnerable to European epidemic diseases for several reasons. First, the Andean population had been largely isolated from the Eurasian disease pool for thousands of years, and it had no acquired immunity to the diseases. Second, the Andean population was concentrated in densely settled highland basins connected by the Qhapaq Ñan, which allowed diseases to spread rapidly. Third, the Andean population was dependent on a complex agricultural system that required a large labor force, and the loss of labor to disease disrupted the agricultural system and led to famine.

A second important cause of the demographic collapse was the social disruption caused by the Spanish conquest. The conquest itself caused substantial mortality, both directly, through the violence of the Spanish armies, and indirectly, through the displacement of the indigenous population and the disruption of the agricultural system. The Spanish civil war of 1537–1542 caused further mortality, as the Spanish factions and their indigenous auxiliaries fought for control of the central Andes. The highland rebellion of Manco Inca in 1536–1537 caused further mortality, as the Spanish attempted to suppress the rebellion and the indigenous population was forced to flee from the war zones.

The social disruption of the conquest also had indirect effects on mortality. The Spanish imposed the colonial mita, a system of labor extraction that required indigenous men to spend a portion of each year working in the silver mines of Potosí or in other colonial enterprises. The mita, in effect, removed a large portion of the adult male population from the highland communities, and the mortality of the mita workers was very high. The mortality in the silver mines of Potosí has been estimated at perhaps 25 to 50 percent over the period of service, and the high mortality of the mita workers contributed to the demographic collapse of the highland populations.

Famine and malnutrition

A third important cause of the demographic collapse was the famine and malnutrition that followed the social disruption of the conquest. The Inca had a complex system of food storage and redistribution, with state granaries and storehouses that could supply the population in years of poor harvest. The Spanish disrupted this system, both by confiscating the state granaries and by imposing the colonial economy, and the indigenous population was left without an effective system of food security. The famine of 1527–1528, which followed the first smallpox epidemic, is reported by the Spanish chroniclers to have killed a large number of indigenous people, and the famines of the 1540s and 1550s, which followed the Spanish civil war and the highland rebellion, are also reported to have been severe.

The malnutrition that resulted from the social disruption of the conquest also made the indigenous population more vulnerable to the European epidemic diseases. The malnourished population was less able to resist the diseases, and the mortality from the epidemics was correspondingly higher. The interaction between malnutrition and epidemic disease was, in effect, a vicious cycle, in which the malnutrition increased the mortality from the epidemics, and the epidemics increased the malnutrition by reducing the labor force available for agriculture.

Consequences of the demographic collapse

The labor shortage

The demographic collapse created a labor shortage that the Spanish attempted to address through the colonial mita and the importation of African slaves. The mita, in effect, was a more coercive version of the Inca mit’a, and it required indigenous men to spend a portion of each year working in the silver mines of Potosí or in other colonial enterprises. The mita was a major source of mortality, and the high mortality of the mita workers contributed to the demographic collapse. The importation of African slaves was another response to the labor shortage, and the African population of the Andes grew substantially in the sixteenth and seventeenth centuries. The African slaves, however, were also subject to European epidemic diseases, and the mortality of the African population was also high.

The labor shortage had important consequences for the colonial economy. The Spanish were unable to extract as much labor from the indigenous population as they would have wished, and the productivity of the colonial economy was correspondingly lower than it would otherwise have been. The labor shortage also had consequences for the indigenous population, since the Spanish attempted to compensate for the shortage by increasing the burden of the mita, and the increased burden of the mita contributed to the demographic collapse. The labor shortage, in effect, was both a cause and a consequence of the demographic collapse, and the interaction between the labor shortage and the demographic collapse was one of the most important features of the colonial economy.

The loss of indigenous cultures

The demographic collapse also had important consequences for the indigenous cultures. The loss of a large proportion of the indigenous population meant that many of the smaller indigenous languages disappeared, and the indigenous cultural traditions were maintained by a much smaller population. The loss of the population also had consequences for the indigenous religion, since the loss of a large proportion of the religious specialists meant that the traditional cults could not be maintained in their full form. The Spanish suppression of the Inti cult in the 1570s effectively dismantled the indigenous state religion in the highlands within two generations of the conquest, and the syncretic form of Andean Catholicism that took root in the colonial period was a mixture of indigenous and Christian elements.

The demographic collapse also had consequences for the Inca heritage in the modern Andean world. The loss of a large proportion of the indigenous population meant that the Inca architectural and engineering heritage was preserved only in a fragmentary form, and the surviving Inca sites — Machu Picchu, Sacsayhuamán, the Coricancha, the Qhapaq Ñan — are surrounded by a much smaller indigenous population than would have been the case before the conquest. The demographic collapse, in effect, was a catastrophe that was unprecedented in the history of the Americas, and its consequences are still visible in the demographic, cultural, and economic structure of the modern Andean countries.