 The leatherworkers, for example, were considered the lowest of the "nyenyo" because their occupation involving animal skins was considered dirty.Slaves have historically been a separate, endogamous group in the Wolof society.Slavery was either inherited by birth in the Wolof society, or were kidnapped, purchased as children from desperate parents during difficult times such as a famine, or slavery was imposed by the village elders as a punishment for offenses.