What makes you so sure mice aren't conscious? Insects probably are not, I have no strong opinion on mice, but dolphins almost definitely are.
I am genuinely interested in your perspective.
I adore my dog. He shows a wide range of what I believe to be genuine emotions. But I do not think he is self-aware, and by self-aware I mean able to contemplate his own existence (and therefor lack of existence). For that matter, I don't think he ever contemplates the lack of my existence (despite feeling it when I am not around, so I am told).
I would expect him to exhibit less reliably to stimuli. His behaviour is closer to a large switch(stimulus){} statement than the emergent behavior of human reaction to situations and stimuli.
One example: he was stepped on when a small puppy by a very old man from that point on and to this day, many years later, he has a major dislike of old people that he does not know well.
If the same thing happened to a child, I would expect the child to slowly, over time, question why they disliked all other old people when the old people they do know are kind to them. This would result in a change of behavior without someone explicitly teaching them.
The only thing that makes humans truly unique is the fact that we can store, retrieve, and process information outside our bodies. While we can question our responses, as in your example, we don't - unless we live in a social environment that suggests we should. (Not all environments do. Some actively discourage it.)
Everything else we do - solving puzzles, counting, acting socially, teaching in person, showing emotions - appears in simple forms in at least some other animals.
Going up a level, humans are actually an extremely large, planet-spanning colony organism with very limited collective consciousness. We act more like an aimless flock of birds or mound-building insects than a collective with awareness of its own planetary situation.
“Tiger got to hunt, bird got to fly; Man got to sit and wonder 'why, why, why?' Tiger got to sleep, bird got to land; Man got to tell himself he understand.”
Other animals then present more consciousness, like chimps, dolphins, elephants etc and would place somewhere between the mouse and humans.
I'm not saying dogs sit around quoting Kant, but they're highly social animals and I find it hard to believe they don't have some internal representation of themselves.
furthermore there is a reason why in Buddhism this intellectual thinking and questioning is considered unessential to being.