In every manner, they were in harmony with nature. By viewing the moon, they were able to keep track of the months, the year, and the seasons. They became used to the vegetation. They were aware of which were edible, lethal, or therapeutic. Each and every animal's behaviors and environment were known to them. Every three years, they burned the vegetation in the woodlands to prevent wildfires and remove game's hiding spots. It never seems to end. Numerous tribes adapted to different types of agriculture. In order to prevent interbreeding, some tribes developed alliances and held annual meetings to sell their pubescent females. Some cultures in California that lived inland traded meals, such as clams and fish, for other goods including pine nuts, acorns, and medicinal plants. Not everybody was fighting. In most locations, most of the time, peace was respected. Greed sparked wars, as shown in the Navajo stealing Hopis crop during the harvest season. Aztec slave hunters, etc.