There was often a stereotype in the antebellum South that slaves were lactose intolerant. However, many slaves had trouble digesting lactose (in dairy products) because it was not a common staple in their diets. Due to the scorching summer heat and the poor quality of the animals themselves, milk became a scarce product only available seasonally. When it did become available, it was first given to whites and if any remained, then to slave children. Additionally, there is some scientific hypotheses behind blacks more often being lactose intolerant than whites today. In West Africa, the presence of the tsetse fly made raising cattle practically impossible, creating a historical situation in which there was no need for humans to develop higher levels of the lactate enzyme (which allows the body to digest lactate).