Large Animal Crossing All animals have a signature, be it size, shape, smell, sound, color, etc., and we can use these signatures to detect and allow or disallow a species of large animal from crossing the border via specially designed tunnels.  A fence that starts wide and narrows to the width of a single animal can be constructed, the narrow section can contain the Signature Sensors and Cameras that identify the animal and allows it to pass through a crossing tunnel before entering the automatic gate system.   People who try to mimic an animal like a deer or mountain lion will be detected and trapped until a human authority figure is dispatched for the arrest.  Index of ... See Drug Only Passage