Behaviors do vary, but the average person when pressed with starvation and dehydration will go to certain lengths to acquire resources and avoid death. And these lengths tend to increase when available energy increases. So the energy usage starts to spike at a certain point when it is waning, before that tipping point in which there is not enough energy available to acquire more energy.
So you figure an individual starting to freak out and thrash about when the hunger starts setting in. Going after animals, tearing up the local flora, etc. to meet that deficit. You start grouping individuals, organizing divisions of labor and compounding and streamlining that labor, and resource exploitation goes up, and you may also have warfare starting to break out if limited resources are to be had between competing groups.
Past a certain threshold of energy usage and technological development, you start getting firearms and explosives and rapid transportation. The utilization of energy correlates with potential energy: the more you are using structurally enables more and more energy to be let loose at once. Indeed, through our collective relations, individually we become a bit like these walking timebombs that can go off past a certain point of decay.
To compound this, mind-body interactions are such that you can start feeling the bite of hunger - and all of the associated psychological and physical turbulence that represents - long before starvation sets in. Especially on a modern grain and starch and sugar diet, with the types of bacteria we are putting in our gut, which begin to antagonize and agitate and send hunger pangs with headaches and foul moods and the like, which have real world consequences. The popular observation of the hungry judge handing down harsher sentences before lunch is one of many examples that comes to mind.
Reflecting this, it is impressive to consider how difficult and complex it really is to smoothly run a modern industrial nation. Modern leaders have to contend with a massive and dynamic population that is constantly expanding and decaying, setting higher and higher benchmarks of living standard and resource usage along its paths of development. As such, governance departs from a simple furnishing of a designated community with the necessary resources to survive, and proceeds to a more intricate and complex balance of interest groups with needs ranging from bare and material to abstract and completely unnecessary. The rich and powerful must be kept happy with preposterous needs, standards, wants, and interests that span the globe.
A single human being can go quite a long time without food. Less time without water, but still a few days. Even less time for exposure, but it doesn't take much for a crude shelter to suffice. But when you start adding these complex social relations, all of that goes out the window. Available shelter changes along profoundly uneven contours: amidst the amazing abundance of an urban environment say, the sheer density sharply limits the creativity of shelter construction for the individual. To be situated higher in the social hierarchy is to be blessed with all manner of modern material comfort, but to be homeless in such an environment is to be in hell with little protection. Social violence and its causes become more complex and chaotic. More far reaching and porous harms such as pollution and mass transportation accelerated pestilence become more salient.
Such uneven development and turbulence reaches all of the way up into the highest economic and political leadership structures of a nation. One can go to war over mere abstractions such as long term financial designs, international treaties and alliances, and speculative access to resource corridors on the other side of the world. And the threat of warfare itself becomes ever more materially and literally explosive as development advances and energy utilization increases, as the potential energy level continues upward. Time marches on, and expansion and decay and the oscillation of those things accelerates and their amplitude deepens.
