According to a paper in the April 28 issue of the journal Nature Methods, laboratory mice and rats very much fear men and become stressed when in their presence. However, it appears that the rodents have no issues interacting with women.
As detailed in said paper, evidence indicates that, when around men, lab mice and rats are about as stressed as they would be were somebody to restrain them in a tube or make them swim around for 3 minutes.
Consequently, the rodents become somewhat less sensitive to pain, and the results obtained while experimenting on them are probably not as reliable as scientists would like them to be, Phys Org explains.
“Our findings suggest that one major reason for lack of replication of animal studies is the gender of the experimenter – a factor that's not currently stated in the methods sections of published papers,” says Robert Sorge with the University of Alabama, Birmingham.
“Scientists whisper to each other at conferences that their rodent research subjects appear to be aware of their presence, and that this might affect the results of experiments, but this has never been directly demonstrated until now,” adds Jeffrey Mogil at McGill University in Montreal.
By the looks of it, mice and rats become stressed when in the presence of men due to the fact that the latter secrete higher concentrations of pheromones than women. These pheromones tell the rodents that they are close to male animals, and cause them to freak out a bit.