Among slave Imports, there had always been a preponderance of males probably at least two males for every female. Whatever the precise combination of factors at work, the beginnings of a sustained natural increase transformed the future prospects of slavery in the South. Slaves imported directly from Africa often struck their owners as more alien than earlier arrival from the Caribbean, and therefore in need of much tighter control. On the other hand, as the numbers of the American dashboard increased, Masters found themselves dealing with the slave population which had known no other life but slavery, and habits of submissiveness could be incilcated from infancy.