Is this something you know to have been attempted or a purely hypothetical scenario?
Something I saw on TV once. They had a room with cupboards and drawers, etc, and a small model of the room which they showed to a gorilla, who watched them hide a model of a treat in one of the model cupboards. When they let the gorilla into the room she immediately went to the analagous cupboard for the treat, even when it wasn't actually there (so she wasn't smelling it, etc.)
I don't, offhand, have the exact details of the experiment. I'm sure we could look it up.
I can certainly imagine a mouse learning that if a certain part of a map was highlighted it would find food in a corresponding area, while still having no concept that the map itself is an abstract representation of the maze it was navigating.
Fair enough. Suppose, though, that a section of the map was highlighted for the mouse for the first time, and that it was for a section of the area that the mouse had never been fed in. If the mouse heads right to that area for the reward, can we then propose that the mouse is actually doing some mental mapping? It seems the most reasonable explanation to me.