“…PratoPrevide, Fallani, & Valsecchi, 2005) which could have created the need for dogs to categorize human gender in order to adjust their responses appropriately. In support of this, shelter-housed dogs petted by women show more relaxed behaviour and lower cortisol levels than those petted by men (Hennessy, Williams, Miller, Douglas, & Voith, 1998), and are more likely to direct defensive aggressive behaviour towards men than women (Lore & Eisenberg 1986;Wells & Hepper, 1999). Although the specific cues to which the dogs were responding cannot be determined from these studies, they do suggest that categorically assessing human gender could be functionally relevant for dogs, influencing their reaction to the individual person.…”