Saw these at Caleta San Juanico. Thought they were a thing. Quick check on the innertubes say they might be common. Dunno.
Anyway, apparently many donkeys have cross markings on their backs, but these don’t look like donkeys or mules to me. They have a very distinct dark mark running from head to tail and another cross line at the shoulders. There were a couple of burros wandering the same “pasture.”
Perhaps there are some horsey people that can clear this whole mystery up. They were very cool looking.