How was the wildlife population kept under control before humans invented hunting?
No offense, but I think you have a confused notion of “under control.” Populations fluctuate based on the resources available and their ability to adapt to the environment. In times of plenty, a species will expand; in times of scarcity, the population will contract. It is a natural process. There is no such thing as “under control” – species continue to expand or deteriorate based on the resources available to them and their ability to survive in a given environment.
Hunting has always been a survival tactic. It was not invented by humans. Many, many animals do it. We’ve just turned it into a past-time, also. And it also depends on what your definition of ‘under control’ is. Mother nature always finds a balance, despite our tendency to try and thwart her efforts.
People didn’t invent hunting, Hunting and predation have existed as long as animals have existed. Man has always been the most successful natural predator which is why we are where we are today, Survival of the fittest rules in the animal world and man worked his way to the top. That is why so many still hunt. It is a natural instinct in humans as well as animals just as a domestic cat or dog still hunts even though he no longer has to. It is still instinctual in many people. We have been the main natural predator of all animals since mammals showed up on the planet and probably the top controller of wildlife populations since that time.