Before the agricultural revolution, the earliest humans relied on hunting and gathering as their food source. The used nature’s resources and their own survival instincts to live. A hunter-gatherer is a member of nomadic people who lived by hunting, fishing, and harvesting wild food. As the number of farmers and herders increased, hunter-gatherer populations decreased throughout history. Kalahari bushmen of the Kalahari Desert of Africa, use persistence hunting, one of the oldest forms of hunting. Before knives, guns, and other weapons came about, humans used their bodies to hunt. They chased their prey until it collapsed. Kalahari hunters chase their prey for 2 to 5 hours over 25 to 35 km in temperatures of about 104 to 107 degrees fahrenheit.