The Columbian Exchange: Reshaping the Old and New Worlds

The Columbian Exchange, following the discovery of the Americas, was a period of longdistance, ocean-going migration of plants, people, animals, and pathogens. The Columbian Exchange remade both New (North and South America) and Old Worlds (Africa, Asia, and Europe) in historically significant ways. American historian Alfred W. Crosby deserves credit for bringing this topic to attention in his 1974 book by the same name.

The Basics.Ancient astronomer and geographer Claudius Ptolemy made maps that depicted only Europe, Asia, and Africa. There was no mention of the existence of the Americas on maps nor in the Bible. Maritime treaties between the Iberian powers had secured the eastern route for the Portuguese, rounding the southern tip of Africa, while the Spanish were forced to sail west to reach India. In four fateful voyages, Christopher Columbus ultimately failed to reach Asia, a fact he would not concede. Those who followed Columbus understood that he had found the Caribbean islands and had touched on one of two large continents: North and South America.

Diseases.These continents supported a rich Amerindian population that had occupied the landmasses over the last 15,000 years. Amerindian societies adapted to all environments and developed a rich agricultural heritage. The domestication of animals, however, was limited to llamas and alpacas of the Camelid family. In the Old World, on the other hand, more than thirteen animal species were domesticated. The close proximity between animals and humans in Eurasia and Africa meant a greater interchange and existence of diseases. These diseases included temperate (smallpox, influenza, measles) and tropical (yellow fever and malaria) varieties. These diseases crossed the Atlantic and reached the Americas. In the absence of reliable population numbers in 1492, the Amerindian population decline can only be estimated. In Central America and the Caribbean, population loss accounted for 90 to 100 percent, whereas South America experienced a loss of about 70 to 80 percent.

The Slave Trade and Slavery.With the Americans partly depopulated by these diseases, labor was in short supply. Europeans, notably the Portuguese, sought to solve the problem by enslaving Africans and forcing them to cross the Atlantic Ocean to labor on a variety of plantations: sugarcane and coffee initially, but the slave experiment expanded to include plantations of rice, tobacco, and cotton. Indigo played only a minor role. The development of plantations in the New World was part of the Columbian Exchange.

An Exchange of Plants. A number of plants cultivated in the Americas crossed the Atlantic and revolutionized agriculture in the Old World: most significantly corn, potatoes, and tomatoes, which allowed for rapid population increases in Africa, Asia, and Europe. Rice was a crop that successfully went the other way. Rice seems almost certain to have originated in East and Southeast Asia. Cultivation is probably about 10,000 years old, making it among the earliest domesticates. A little later, Africans domesticated rice, but this was a brand-new species and seems to prove that the African experiment with rice was independent of anything Asia had done. In the Middle Ages, the Muslims introduced rice to Europe. Europe never had much success growing rice and imported it from Asia. In the Middle Ages, Europeans did not seem to know that Africa produced rice.

The Columbian Exchange was dramatic. Now Europeans brought rice to be grown in coastal South Carolina and Georgia. Yet this was not Asian rice. The first types of rice and the first slaves came from regions of West Africa that specialized in rice culture. Most of this rice was exported to Europeans, who were now eating African rather than Asian rice. Because the rice was husked during processing, there was no way for Europeans to know that they were no longer eating Asian rice. Rice cultivation in the Carolinas also allowed for perfect breeding conditions of the Anopheles mosquito, the main transmitter of malaria.

Animals and the Columbian Exchange.The livestock of Europe, Asia, and Africa made a deep imprint on the Americas. Consider the cow. A Eurasian domesticate, the cow was an important animal in large parts of East and West Africa. As an Old World animal, it produced meat, butter, milk, and cheese. The question of whether the masses could afford these products is important, but we cannot solve it here. Columbus brought cows and pigs to the Americas. Both have been enormously important. The cow populated large parts of South America, especially the Argentine pampas. So large did herds become that many cows went feral. A person could find one or more cows wherever he or she went, shoot one, and have plenty of meat for the family. The pig made a similar transition. It was raised throughout the Americas. Of particular importance was the American Midwest, where farmers found that the pig transformed their corn into pork. Cities like Porkopolis (Cincinnati) and Chicago arose as centers of a meat-packing industry that pigs and cattle made possible.

The horse is a curious case because it was indigenous to the Americas. During the last Ice Age, horses crossed the land bridge between Alaska and northeastern Asia, spreading to all parts of the Old World. It then went extinct in the Americas. But the Columbian Exchange reintroduced the horse to its continents of origin. Native Americans then adopted the horse and the greater mobility it afforded. The Plains Indians used it to hunt bison, creating the often-perpetuated stereotype that Native Americans had domesticated the horse when arriving in the Americas.

Insects.Insects are important carriers of diseases. Consider Aedes aegypti, the mosquito from tropical Africa that carries the virus that causes yellow fever, an often fatal disease. Very early in the European conquest, African slaves brought the mosquito and the disease to the Caribbean islands. The result was catastrophic in a somewhat novel way. The pattern of disease transmission had been from European or African to Amerindian. In tropical America, yellow fever killed large numbers of Amerindians, but because Europeans did not have much immunity to tropical African diseases like yellow fever, they suffered too. In some cases, yellow fever, not military prowess, determined the outcome of battles. Christopher Cumo

FURTHER READING:Crosby, Alfred W 1972. The Columbian Exchange: Biological and Cultural Consequences of 1492. Westport, CT: Greenwood Press.

Crosby, Alfred W 1987. The Columbian Voyages, the Columbian Exchange, and their Histories. Washington, D.C.: American Historical Association.

Crosby, Alfred W 1994. Germs, Seeds, and Animals: Studies in Ecological History. Armonk, NY: M. E. Sharpe.

Diamond, Jared. 1997. Guns, Germs, and Steel: The Fates of Human Societies. New York: W W Norton.

McNeill, John. 2010. Mosquito Empires: Ecology and War in the Greater Caribbean, 1620-1914. Cambridge: Cambridge University Press.