326 DAVID M. LEWIS
recently added several further reasons to believe this to be the case.^56 That said,
the socio-economic organization of helotage was profoundly different to Attic
slavery, and even from a legal point of view several state-imposed rules inter-
fered with helot ownership in a way that would have seemed rather odd to an
Athenian slaveholder. Helotage is one of the rare examples in world history
of a slave population that succeeded in perpetuating itself from generation to
generation solely through natural reproduction; we might view it as a histor-
ically functional example of self-sufficiency, at least in terms of slave supply. It
thus serves as a useful counterpoint to Athens in assessing the degree to which
the latter went beyond such self-sufficient strategies.^57 In lieu of attempting
quantification, I aim for now to sketch in the salient factors that shape the
demographic dynamics of slave populations; for this, cross-cultural comparison
is invaluable.
To understand the factors that affect the demographic performance of slave
populations it is perhaps best to turn to the New World, for which detailed
data survive, and which has been the subject of sophisticated debate over the
last few decades. Despite the fact that all New World slave populations ulti-
mately derived from (mainly Western) Africa, strikingly different demographic
patterns can be observed in the individual populations into which these slaves
were integrated. The territories that would become the United States (rather
surprisingly) imported only a small fraction of the overall number of slaves
exported from Africa to the New World, somewhere around 4 percent.^58
Favourable conditions meant that the U.S. slave population generally grew
over time, even after the closure of foreign supplies in 1808.^59 The reproductive
success of the U.S. slave population contrasts starkly with the bleaker demo-
graphic performance of regions such as the Caribbean and Brazil, which relied
on the regular injections of bodies through foreign trade to maintain overall
numbers. A complex nexus of factors explains these differences in perfor-
mance, and what follows can only be taken as a crude outline, a broad sketch
of the most significant variables.
On the negative side, several factors in combination added up to a lethal
cocktail in the Caribbean and Brazil. Sugar production was a major compo-
nent of the slave economies in these regions, and Tadman has illustrated how
the regime of sugar growing united many of the variables that cripple the abil-
ity of a slave population to successfully reproduce its numbers. One variable
is the ratio of male to female slaves; the more top-heavy the quota of males to
females, the less likely the population is to reproduce successfully. Sugar pro-
duction was physically punishing, especially the October to January ‘grinding
season’ which entailed long hours and physically draining tasks. Plantation
owners required a largely male workforce,^60 and the dangerous labour regime
heightened mortality and lowered fertility rates; coupled with a hostile dis-
ease environment, sugar plantations generally fell on the wrong side of the