perhaps due to past generations of male experimenters, mice have developed a central nervous system which deadens pain in the expectation of a painful experiment when exposed to male scents.
What would be the selective advantage of pain resistance in the context of a lab environment? It seems to me like the rodent's chance of passing on it's genes would have no correlation with resistance to pain.
We know that pain stresses the nervous system, and that it also increases incidence of depression. Both pain and depression lower survival chances, as they both increase the chances for negative effects on the host such as sudden weight fluctuation, abnormal sleep cycles, and uncoordinated muscle control.
I have not worked in such a lab setting, so i'm unsure if any of the mice that survive experimentation are exterminated or repurposed.
If repurposed, one can imagine that a pain-reduction schema would be useful in such environments for the sake of species proliferation. Mice/rats better suited to the pain thresholds required of them would eat better, sleep better, and ultimately breed more.
perhaps due to past generations of male experimenters, mice have developed a central nervous system which deadens pain in the expectation of a painful experiment when exposed to male scents.