We've recently had a new boy into our pack from some friends who could no longer cope due to illness, he is 2 yrs old and has settled in quite well but he marks the strangest things.
We have a water bowl and food bowl on our marble fire grate, he marks the marble grate quite often. He also marks the water bowl and if the food bowl is empty he will mark this.
Sorry, no males in this household due to that very real problem! I had one male dog, and since that time, no more! He used to mark my Mom's bathroom towel, and the corner of my bedspread. Nothing else.