I saw nothing that night at the tanks.
The next night I went back to the cattle pen blind. I took a couple of camo t-shirts to mask my silhouette on the brush behind me.
At about 9:30 I heard a huffing noise to my left maybe 10 yards behind a mesquite bush that was maybe 6 or 7 feet away. I was sure it was a lone boar based on the sound. Then I heard a popping noise and figured he was popping his teeth. He huffed again and again, and kept popping his teeth. It sounded like he was spoiling for a fight. The wind was in my favor, and I thought that perhaps he had another boar over there that he was challenging.
He popped his teeth and huffed louder and louder for 45 minutes without moving toward me, trying to get downwind of me, or exposing himself in any way to the possibility of getting shot. I finally figured out that he knew I was there but was unsure of what I was, so he just stood in the same place and made noise. at about 10:15 he stopped.
By the sound of his deep, bass-tone huffing he must have been a beast of a hog. And he was smart enough to not expose himself to me. It was a pretty exciting night that I will never forget. I would love to get another crack at that hog.