However, historically their numbers were estimated to be 25 million. Deer, another prey animal, was estimated to be 200,000,000 in 1450, before Europeans came to North America. I would suggest the higher numbers for both could be considered natural for the purposes of keeping the species genetics varied enough for continuous healthy evolution, but low enough to exist regionally without stressing their ecospheres to the point of where their food supplies collapse over a wide range. Because they don’t have brains like ours, they are constrained by nature.

We must understand nature the best we can, including our own human natures, and learn from it all. Then, when there finally is an international consensus of how we must have a lower population, we will have the right information on hand to quickly pick a world-wide population number — and design a way to get to it.

And yes, I personally believe that we will have to choose a target number and not leave it to chance. Leaving it to chance will allow regional interests to make exceptions for various cultural and religious regions, usually to give power to a select few.