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

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.