My dog demonstrated one of the two possibilities earlier this week. I'm still not sure which.
I'd gone into the kitchen to get a drink of water, and made note of the bowl of puppy food (half full), then filled the water. She followed me, and buried her nose in her bowl. I went back in and sat down.
A few minutes later, I heard her get a drink, then heard the bottom of her dish scrape over the floor (rubber on linoleum).
Next thing I knew, there was an empty food bowl sitting on my foot, and a Scotty puppy staring at me. When I looked at her, she looked down at her bowl, then back up at me.
I took the bowl, filled it, and she emptied it again, but seemed satisfied, that time.
I thought it was a fluke, until she did it again last night.
So I ask you: smart dog, or smart ass dog?
6 minutes ago