Looks like a rat to me. Big feet, big nose.
Agree, mouse.
Seems pretty divided. This should have been a poll. 
It’s a rat: 6 votes
It’s a mouse: 5 votes
It’s a rodent: 1 vote
Looks like a mouse to me.
I too immediately thought mouse when I saw it. But upon googling pics of both, I’m now unsure.
This is a mouse. Rats are huge. Way bigger than what I see in the picture.
But rats don’t start out huge. I’m inclined to side with the young rat people (as I mentioned above.)
Baby kangaroo.
R.O.U.S.
Mouse fur tends to be shorter and denser, it would help if we had some scale, is this a small or large cat?
Super-intelligent pan-dimensional being that wants to remove and examine my brain in order to secure a lifetime gig on the talk-show circuit.
its a strange foto, but salazarrr(sisters kat) is now 4.5 kilograms
picture from a few years ago
e.t.a. yes you may put captions on both foto’s if you want to
Check his wallet. If his or her name starts with an “M” (Mickey, Mortimer, Minnie, etc.), it’s a mouse. Otherwise, it’s a rat.
wasn’t Moriarty a Rat in some cartoon?
Hullo? Um…Jerry?
And of course there’s Pinky and the Brain - both mice if I recall.
And Fievel and his family as well.
That is clearly photoshopped. The shadows are all wrong. It is a goldfish. You can still see the gills near the neck.
I’ve handled a lot of lab rats and some lab mice. Mice have distinctly thin tails and distinctly big ears–somehow a more delicate look. The photo is consistent with an immature rat. I guess if someone said it was some sort of rat relative, and not * rattus rattus* or rattus norvegicus (blanking on common names) I’d believe them, but just too chunky for a mouse.
Clearly it’s a mroust.