WIKIPEDIA ON SHEEP
Wikipedia states, "Sheep have good hearing and are sensitive to noise when being handled. Sheep have horizontal slit-shaped pupils, possessing excellent peripheral vision with visual fields of approximately 270° to 320°, sheep can see behind themselves without turning their heads. However, sheep have poor depth perception; shadows and dips in the ground may cause sheep to balk. Sheep can become stressed when separated from their flock members. Sheep can recognize individual human faces and remember them for years. Sheep are frequently thought of as extremely unintelligent animals. A sheep's herd mentality and quickness to flee and panic in the face of stress often make shepherding a difficult endeavor for the uninitiated."