I have said for years, dogs are fine, but they don't speak. Perhaps you can teach them to bark a certain number of times when they sense a particular drug or explosive ( which would be a cool trick), however, with more than 50 volitiles, it would be incumbant upon the handler to be ready to not lose count. But for real, again, dog's are great. they run fast and can track fast. however, the handheld units can be used as a supplement to immediately identify the type of threat.