One of these steroidal compounds, androstadienone, is present at much higher concentrations in male sweat and can be detected by women, albeit with wide variation in sensitivity. Pheromones may be present in all bodily secretions but most attention has been geared toward axillary sweat which contains the odorous 16-androstenes. Yet pheromones can be detected by the olfactory system although humans under develop and underrate their smelling sense. Many examples exist in animals but their role in humans remains uncertain since adults have no functioning vomeronasal organ, which processes pheromone signals in animals. Pheromones are substances which are secreted to the outside by an individual and received by a second individual of the same species.
