Rather the lip-smacking variability likely reflected how individual differences and environmental factors, and even social conventions, affect how chimpanzees communicate with each other.
Because we are recently descended from a small founding population, there hasn't been time enough or people enough to provide a source of great variability.
Of course, viewed from a different perspective, this blindness to local cultural variability is precisely what makes statistics vulgar and potentially offensive.
Physiological benefits such as our heart variability, which is a predictor of longevity, which is a predictor of health is increased. The parasympathetic system increases when we are grateful.
It could be because of greater natural variability in the climate, because clouds dampen warming or because of some other little-understood mechanism in the almost infinitely complex climate system.
Since the dawn of time, several billion human (or humanlike) beings have lived, each contributing a little genetic variability to the total human stock.
So it's the combination of all these factors playing out to differing degrees in different animals that explains the variability we see in the animal kingdom.
While there's tons of variability between testers, protocol calls for no less than two milligrams of sunscreen per square centimeter of skin and that's significantly more than people tend to use in real life.
So, just set up, you know, what was the purpose of what you were doing—to try to understand the climate variability of this area—and what you did, and what your approach was.