So horse sense means thinking before acting and taking the cautious approach. Lately, it's also come to mean common sense . Being prey affected horse development and behavior. A horse's primary defense mechanism is running away. They will put up a fight when frightened and cornered.
Horses have five senses but they are developed in a much different way than humans.
Sight - A horse has about 330 degrees of horizontal vision. Given that a circle is 360 degrees that's pretty amazing. A horse's blind spots are approximately 15 degrees of arc directly in front and 15 degrees of arc to the rear. Hearing - Horses' hearing is both sharper and broader in range than humans. They may start at unfamiliar sounds, but will usually investigate and remember the sound.