The systems theory has the answer.
Systems are (1) sets of related (2) parts, but not only that: we (3) interact with them.
Let's start with (2): there is no possible physical proof that you are or not a dog: in the realm of essential parts, everything is just atoms. You and a box of chocolates are the same: energy.
Now, (1): when parts (e.g. atoms) form relations (e.g. bonding), systems are formed (e.g. molecules). Small systems form bigger systems (e.g. particles, cells, membranes, teeth... etc.). But they are just that: living or non-living systems. But at that level, there are no objective differences. At this level, boxes of chocolate are different of living entities. But there are no interactional differences between living beings.
Essential differences of systems start on the subject (3): us, when interacting with systems. A dog is a subjective idea, obtained by means of interaction: at some point in my life, I interacted with a dog, so I knew dogs. A dog is an experience of an interaction (as every idea on my mind).
Therefore, the fact that you are or not a dog is absolutely a subjective understanding. So, for me, you are not a dog because you formulated a question, and on my experience interacting with dogs, dogs cannot formulate questions. If you would have sent a furball... that would have complicated my personal proof: my interaction with real furballs is zero, essentially, heard some jokes on tv.
Now, it is impossible to prove that you are not a dog, because it is a subjective understanding. But that's how systems work in our mind. We share subjective experiences.
You cannot prove that the green color you see it is the same I see. But we name each subjective perception "green" and that's enough to survive. You and me call those things "dogs", play with them, but we're not sure we have the same perception. As soon as we interact with some physical system, we know if it is a dog or not.
In simpler words: trust me, you are not a dog.