They compared track sizes to determine which animal to track and hunt for supper. As scientists, they developed hypotheses of how to follow animals. Natives had to TEST their hypotheses everyday in the field. Their answer was either we go hungry tonight or we eat. Therefore, natives became great practitioners of their tracking skills.
Tracking is a science and has been since the beginning of hunting.
As a science, each technique is a hypothesis which must be testable. The goal of science is to disprove hypotheses and replace them with better working hypotheses that in turn will be tested. Once trackers identify a good working hypothesis, it is taught but still with the goal of testing during its use. Tracking scientists prove hypotheses wrong for the betterment of our science. Natives used the scientific method of disproving hypotheses and they taught the scientific method.