Gender Differences in Maternal Intervention in Jeju Ponies (Equus caballus)

We investigated interventions by mother Jeju ponies on Jeju Island, Korea, to determine whether mothers assisted their offspring to attain higher status within the dominance hierarchy. Because dominance rank is important within each gender, we predicted that mothers would be more likely to intervene when their foals were play-fighting with foals of the same gender. A total of 173 play-fighting events were recorded from March to October 1998 and from April to October 1999. Of these, foals were more likely to play-fight with a foal of the same gender as with a foal of the opposite gender (120 versus 53 occurrences, respectively). A mother of one of the foals that were play-fighting intervened in 17 of these interactions. Contrary to the prediction, a mare was more likely to intervene when opposite genders interacted than when the same gender interacted. Analyzing interactions between the opposite genders further, mothers were equally likely to intervene when a daughter was play-fighting with a male foal as when a son was play-fighting with a female foal. Hence, mothers were not more protective of daughters than sons. Mothers that were in the younger age class ($2\sim11$ years old) were as likely to intervene as those in the elder age class ($17\sim25$ years old). However, all foals that were harassed were offspring of mothers in the younger, more subordinate age class. intervention directly maintains the dominance rank of the intervening mother, and may indirectly assist the intervening mother's foal to achieve a higher dominance rank. By discouraging their foals from play-fighting with the opposite genders, dominant mothers may be encouraging their foals to play-fight with the same gender and participate in establishing its own dominance rank.