breeding females may advertise oestrus (being "on heat" or "in season", i.e. that they are fertile, ovulating and receptive to breeding) with pheromones (scent), courtship behaviour, and visual signals. human females have long been thought to conceal their ovulation, but women's behaviour changes around the time of ovulation with increased sexual motivation, and they are more attracted to men at that time; conversely, men are more attracted to the scent of women around the time of ovulation than in the non-ovulating (luteal) phase of the menstrual cycle.