The conflicts between different groups of Indians played right into the hands of those who would exploit them. Conflicts over hunting grounds are the classic bases of the animosities between Indian groups. The antecedents of the historic Indian nations were migratory hunters. When the hunters were few, and the game was plentiful, good leaders could keep conflicts between their peoples to a minimum. But when the hunters began to compete for the same animals, nationalism was the next development.
Nations are the leader's way to keep people organized to prosecute their competitive conflicts.
When the Woodland peoples migrated to follow herds, they supplemented their meat diets, as the bears do, with berries, nuts, and other vegetables, and a variety of fish, arthropods, shellfish, grubs, and so on, depending on their tastes and circumstances. According to official doctrine, the earliest hunter and agrarian peoples of America came to this continent from Asia. With urbanization, the people of the Adena and Hopewell cultures began to experience supply problems, particular where food was concerned. The Hopewell were a long-headed people, like Europeans. Late in their culture the Hopewell people began to flatten their heads.