If you are buying a horse for the mountains, you should select one with good withers, legs and feet, and with a disposition suited to your ability. Like most domestic animals, horses have a descending order of authority or 'pecking order . Usually a mare will be the leader of a herd unless a stud is present. Caution must be used in the placement of horses in a pack string, at a hitch rail, or in a truck to avoid trouble or injury. Some horsemen prefer geldings over mares, while many feel that individual disposition is more important than the sex.
Some mares can be troublesome during estrus.
Like people, horses are individuals, and although they usually follow general behavior patterns, they sometimes react differently in the same situation. A horse that is completely reliable under any other condition may have an abnormal fear of one thing. Training, and the methods used, play a large part in shaping a horse's behavioral patterns. Due to the individuality of the horse, methods of training must often be tailored to its particular disposition. If you borrow horses, you have the disadvantage of knowing little of the horse's temperament.