Short Change

A Horse walks into a bar, orders a beer, sits down at one of the tables, and starts reading his paper. The bartender is a bit shocked by all this, but pours the beer, and brings it over to the horse, who proffers a ten dollar bill for it.
Now the barman figures the horse isn't that bright, so he decides to pull the old 'short-change' trick on him. He duly goes back to the horse with 1 dollar. The horse doesn't say a word. The horse eventually finishes his beer and goes up to the bar to order another.
The bartender says to him, "You know, we don't get many horses in here."
To which the horse replies, "At nine dollars a beer, I'm not surprised!"