In the New World, domestic animals were not common and therefore most meat was hunted and gathered, while in the Old World domestic animals such as cows, horses , pigs, etc. they were very common in villages of the same stature as those in the Americas, so the lifestyles were different with different habits. Furthermore, the epidemiological imbalance resulted from the amount of disease arising from the old world and its domesticated animals compared to the diseases found in the Americas. Overall, the old world, Europe, had many more diseases that were easily transmitted. Furthermore, Mann calls the disease imbalance the most important fact in world history because when these diseases were transmitted to the Americas, they dictated the first 150 years of life of Native Americans as they did so many others.