During the heyday of the American fur trappers in the west, they openly and knowingly violated the law of the United States that forbade such activity. Several American officials and representatives of the Federal Government indicated that they understood trapping and hunting on Indian lands was contrary to the law of the land. They described the devastating effects of fur trapping by whites: how it undermined other policies of the United States relating to Native Americans. Some tribes in the first third of the nineteenth century were characterized as warring, insensate savages, including the Arikara tribe and the Blackfeet. The hostility of these tribes was not senseless: they had good reasons to believe that representatives of the United States were their enemies. They entered directly into hostile actions when opportunities arose, of course, but in most cases they believed that they were fighting for their very survival. In general, history has proved them to have been correct in this assessment.