Toronto, April 29 (IANS) Know why, to the delight of your spouse, that stubborn mouse runs the moment he sees you entering the house from office? Because even the smell of a man could elicit fear in mice and rats, a fascinating research has revealed.

This happens because hardwiring of some animals may cause them to react differently toward men or women.

To understand this, Jeffrey Mogil and his team from McGill University in Canada induced pain in mice and then compared facial grimacing of the mice in the presence of either a male or a female.

The mice in the presence of men showed increases in body temperature and corticosterone (stress hormone) levels.

The researchers found same results when the female wore a T-shirt previously worn by a man.

It could be that testosterone or male pheromones trigger fear in rodents, but the exact reasons remain a mystery, the study, published in the journal Nature Methods, concluded.