After reading the article it sounds absurd when you first think about it but leaves you with how else could it possible work after seeing the evidence.
I am no evolutionary biologist but one might look at rapid adaptation as an evolutionary strategy in itself. I have always felt humans did this by using intelligence. Does anyone know of other mammals that can live in such a large range of environments without physically adapting?
Humans have physically adapted though. Skin and eye color, subcutaneous fat, underwater vision, high-altitude adaptations, resting body temperature, nose shape and nostril size, etc. We just haven't had populations separated long enough to be unable to breed or be considered separate species.
There are certainly other ways it could work. The variability that Stroud was surprised to see might not have occurred. Or it might have resulted in persistent change rather than stability.
Variability varies among species, and high and low variability can both be seen as evolutionary strategies that are suitable for different ecologies.
Humans using intelligence is not biological (genetic) evolution, it's mimetic evolution. But we employ other sorts of physical but non-biological mechanisms to adapt, like clothing and housing. Dogs accompany us and can survive in many environments by living in our homes and depending on us for food. Also lice, bedbugs, etc.
I don't get point of your question, but why limit it to mammals? Spiders, bacteria, and viruses are everywhere with few environment-specific adaptations.
I am no evolutionary biologist but one might look at rapid adaptation as an evolutionary strategy in itself. I have always felt humans did this by using intelligence. Does anyone know of other mammals that can live in such a large range of environments without physically adapting?