Females of these species benefit as males give them more time for feeding, protection for their young, and protection from predators and harassment by outside males. Among females in a harem, a linear dominance hierarchy exists based on the time at which they join the group. Harems travel in a consistent filing order with the high-ranking mares and their offspring leading the groups followed by the next-highest ranking mare and her offspring, and so on. The family stallion takes up the rear. Young of both sexes leave their natal groups as they mature; females are usually herded by outside males to be included as permanent members of their harems.