Why horses?
Remarkably, the hip movement of a walking horse is very similar to that of humans.  Hippotherapy is the term used for the physical, occupational and speech therapy treatment strategy that utilizes equine movement.  “Hippo” is the Greek word for horse.  Hippotherapy has been shown to improve muscle tone, balance, posture, coordination and motor development, as well as emotional well-being. 
The American Hippotherapy Association notes:
 “The horse's walk provides sensory input through movement, which is variable, rhythmic, and repetitive. The resultant movement responses in the patient are similar to human movement patterns of the pelvis while walking. The variability of the horse's gait enables the therapist to grade the degree of sensory input to the patient and then utilize this movement in combination with other treatment strategies to achieve desired results. Patients respond enthusiastically to this enjoyable experience in a natural setting.”