4 From the 1660s, however, the colonies began enacting laws that defined and regulated slave relations; central to these laws was the provision that black slaves, and the children of slave women, would serve for life. By the eve of the American Revolution, slaves constituted about 40 percent of the population of the southern mainland colonies, with the highest concentration in South Carolina, where well over half the population were slaves.
Slaves performed numerous tasks, from clearing the forest to serving as guides, trappers, craftsmen, nurses, and house servants, but they were most essential as agricultural laborers and most numerous where landowners sought to grow staple crops for market. The most important of these crops consisted of tobacco in the upper South (Maryland, Virginia, North Carolina) and rice in the lower South (South Carolina and Georgia); farther south still, on Caribbean islands such as Barbados, Jamaica, and Saint-Domingue, sugar was an even more valuable slave-grown commodity. Slaves also worked on large wheat-producing estates in New York and on horse-breeding farms in Rhode Island, but climate and soil restricted the development of commercial agriculture in the Northern colonies, and slavery never became as economically central as in the South. Slaves in the North were typically held in small numbers, and most served as domestic servants; only in New York, with its Dutch legacy, did they form more than 10 percent of the population, and in the North as a whole less than 5 percent of the inhabitants were slaves.
By the mid-18th century American slavery had acquired a number of distinctive features. Well over 90 percent of American slaves lived in the South, where demographic conditions contrasted sharply with those to both the south and the north. In Caribbean colonies such as Jamaica and Saint-Domingue, blacks outnumbered whites by more than ten to one and slaves often lived on huge estates whose inhabitants numbered in the hundreds; in the Northern colonies, blacks were few and slaves were typically held in small groups of less than five. The South, by contrast, was neither overwhelmingly white nor overwhelmingly black: slaves formed a large minority of the population (in some areas, of course, they formed the majority), and despite regional variations, most slaves lived on small and medium-sized holdings containing between 5 and 50 slaves.
A second distinctive feature was the rapid “Americanization” of both masters and slaves. English colonists quickly came to feel “at home” on their American holdings. Few sought to make quick killings on their planting ventures and then retire to a life of leisure in England, and the kind of absentee ownership common in much of the Caribbean was relatively rare in the American South; instead, masters typically took an active role in running their farms and plantations. Equally significant was the shift from an African to an African American slave population. By the eve of the American Revolution, only about 20 percent of American slaves were African-born (although the concentration of Africans remained higher in South Carolina and Georgia), and after the outlawing of new slave imports in 1808, the proportion of African-born slaves became tiny. The emergence of a native-born slave population had numerous important consequences. To take one example, among African-born slaves (imported primarily for their ability to perform physical labor) there were few children and men outnumbered women by about two to one; American-born slaves, by contrast, began their slave careers as children and included approximately even numbers of males and females.This shift from African to African American was closely related to a third distinctive characteristic of American slavery that was in many ways the most important of all: in contrast to most other slaves in the New World, those in the United States experienced what demographers refer to as “natural population growth.” Elsewhere, in regions as diverse as Brazil, Jamaica, Saint-Domingue, and Cuba, slave mortality rates exceeded birth rates, and growth of the slave population depended on the importation of new slaves from Africa; as soon as that importation ended, the slave population began to decline. At first, deaths among slaves also exceeded births in the American colonies, but in the 18th century those colonies experienced a demographic transition as birth rates rose, mortality rates fell, and the slave population became self-reproducing. This transition, which occurred earlier in the upper than in the lower South, meant that even after the outlawing of slave imports in 1808, the number of slaves would continue to grow rapidly; during the next half century the slave population of the United States more than tripled, from about 1.2 million to almost 4 million in 1860. The natural growth of the slave population shaped a distinctive slavery in the American South and hastened the transition among slaves from African to African American.