Pacers are horses that pace instead of trot at the medium speeds. This means pacers will have a two-beat gait with lateral symmetry, in which the foreleg and hind leg of the same side will have identical suspension and weight-bearing phases in their stride. This is in contrast to the trot, where they have a two-beat gait with lateral asymmetry, in which the foreleg and opposite hind legs will have identical suspension and weight-bearing phases. Ambling horses are smooth-gaited horses that have a gait that is very similar to the pace, except there is a fraction of difference between the suspension and weight-bearing phase of the foreleg and hind leg of the same side, which gives rise to a four-beat gait with very short intervals between beats. The ambling gait is more energy efficient than trotting and at one time the most revered warhorse was one that could both amble and trot. In herds of amblers, few horses are born that will only amble or only trot; instead, most do both. In colonial Chile amblers that were referred to as pacers was one of the three types of horses produced by horse breeders.