Help! Is this a hamster, mouse or rat?

[HamHelp]

I caught a little friend today. He bit me, but it just barely broke the skin, so im not too worried. However, im not sure what this is. Could this be a hamster? It has a very small tail, its face isnt as long as a mouse or rat. Im not sure, but it was in our apts floor vents. Which im sure connect to other apts. Maybe a lost pet? Its very tame, doesnt mind being held and immediately nested when I placed shredded toliet paper in its temp home. Attached files below. Thank you!