Well—there's a thought experiment of something like a 'dark universe'—a universe devoid of conscious observers, with the absence of awareness and perception while the physical processes continue unabated just as ours does with all of the people walking around, doing business, living cosmopolitan lifestyles, etc. This is theoretically possible because humans are just agents with brains that bring in stimuli, process it, and react. I.e. consciousness is not a necessary part of the equation to realize the universe is currently realized. The only reason we know consciousness is part of the equation, is because we experience it ourselves.
So I don't know if the fact that your cats are agents that are reacting to stimuli is proof that they're conscious. Again, if we were an outside observer, like an alien, we would have no way to prove humans are conscious. The only reason we believe scientifically that other humans are conscious is because we personally perceive conscious, and since other humans have the same neurological structures that we do, we can posit that they experience the same thing. Philosophically though we can't 'prove' other people are conscious, which gets us back to the philosophical zombie thought experiment.
