The benefits of living close to other people are evident even to hunter-gatherers. Though their societies have changed over the millennia, studying characteristics of present-day hunter-gatherers can let us peer into the past. That’s what was done by three anthropologists—Marcus Hamilton, Bruce Milne, and Robert Walker—and one ecologist—Jim Brown. In the process, they seem to have discovered a fundamental law that drives human agglomeration. Though their survey of 339 present-day hunter-gatherer societies doesn’t explicitly mention cities, it does show that as populations grow, people tend to live closer together—much closer together. For every doubling of population, the home ranges of hunter-gatherer groups increased by only 70 percent.
[Link to Density is Natural]