Each species acquires, by means of natural selection, genetically fixed physical and behavioral characteristic which help to insure its survival in its natural environment. In the case of the horse, principal physical characteristic which helped it to survive is speed, and the principal behavioral characteristics which enables that speed to be an asset to the wild horse is flightiness. The horse is a grasslands dwelling species. Its major natural predators are the great cats, and its primary means of survival is instantaneous flight when frightened by an unfamiliar sensory stimulus. The stimulus may be visual, olfactory, tactile, auditory, or a combination of any of these. The flightiness of the horse is the reason he so often injures himself or the people who handle him, and it is the reason he is so often perceived as a stupid animal. But, the horse's flightiness is not stupidity. It is nature's wisdom and helps the horse to survive in his natural open environment. The horse is a timid creature, and his timidity and flightiness are genetically fixed traits which have been modified but not eliminated by generations of domestication.

The ass and its hybrid offspring, the mule, are renowned for their comparative lack of flightiness. I believe that this can by explained by the fact that the ass' normal habitat is precipitous, rough terrain. The instantaneous flight reaction when frightened could be fatal in such an environment. Therefore, when entangled in barbed wire, the horse typically panics and injures himself, whereas the ass or mule will typically "stay put."

Fear is contagious to a horse. This serves as a survival mechanism in wild horse herds. It is the reason that a young horse gets excited when another horse runs by him.

The horse can be quickly habituated to any frightening but non-painful sensory stimuli, including sound, sight, touch and odor. Once habituated to a specific frightening but non-painful sensory stimulus, the horse will retain its familiarity with that specific stimulus indefinitely. Habituation to such frightening but non-painful sensory stimuli is accelerated by repetitious exposure. For example, a gun shot may frighten a horse and cause him to attempt to flee but, if confined and exposed to repetitious gunshots, the horse is further enhanced if the repetitious expose is rhythmically applied. Habituation is still further enhanced if repetitious, rhythmic stimuli are simultaneously applied. Thus, tactile, auditory and visual stimuli, applied simultaneously and rhythmically, will quickly habituate the horse to all of these multiple stimuli. The stimuli may be frightening but non-painful, and it is essential that the subject not be allowed to escape before habituation occurs, or future exposures to such stimuli will result in increased panic rather than acceptance.

A good example of the habituation process is the "sacking out" of a colt by the horse breaker. The colt, confined so that he cannot escape, is repeatedly stroked with a waving sack or blanket. The sight, sound, smell and touch of the sack are frightening. However, rhythmically and repetitiously applied, the colt soon is habituated to the sack, and he remembers this lesson permanently, If one side of the horse is "sacked out," however, the horse lacks the power of reason to apply what he has learned to his other side. We are now dealing with a different eye and a different side, and the lesson must be started anew. Generally, I have found that it takes about 30 stimuli to habituate most horses. The moment of habituation can be detected. The fear response cases, and instead the horse's eye wanders from the source of the fear-provoking stimulus. He is no longer aware of it. He is habituated to it and, providing it is identically presented in the future, he will not fear it again. Be warned, however, that even minor variations in the stimuli may elicit future flight responses.