We share common ancestors with houseflies who have a day to find a mate. We were at one point small furry proto-mammals who mated almost exclusively by smell a

We share common ancestors with houseflies who have a day to find a mate. We were at one point small furry proto-mammals who mated almost exclusively by smell and aggressiveness. It no longer takes too long to evaluate intelligence. But when our mate evaluation systems were being designed, there were fewer available dimensions to optimize over. A woman's opinion of a man's smell still correlates strongly with both her menstrual phase and their mutual genetic suitability.