We don’t know whether Winx has perfect structural symmetry. But her trainer and regular riders would have a strong sense of the mare’s balance during track work and races. Bilateral symmetry in animals refers to the balance of structures, such that they are mirror images along the body’s midline. Asymmetry is a disruption of the left-right balance that may be associated with factors such as abnormal anatomy, chronic lameness, or laterality (a preference to use one side of the body rather than the other).