I have experienced a bull barking. My buddy and I had a bull barking at us for 45 minutes one morning. We were cow calling and it was pacing back and forth just out of bow range on the hillside above us. The bull kept barking at us as we were hidden in the trees and I was an idiot and had forgotten my bugle back at the car. We kept cow calling and had him all worked up, he had some cows with him that had gone up the hill.
The sound of the bark was a loud gutteral bark that echoed through the area. Based on what I observed that day I felt that elk's bark was definitely a show me bark attempting to get visual confirmation of his cows and/or attempting to get his cows up the hill to him. Even though we didn't get the bull, it was one of the coolest experiences I have had with calling to bulls.
