I find our assumption that other living beings are not self aware fascinating. Simply because we cannot speak a common language we assume creatures are drones with no intelligence or emotion, until we can somehow prove otherwise. It almost speaks more to the human psyche than anything else.
I think it’s more that scientists have tried testing animals for self-awareness for many years, and most animals fail any test they’ve devised. Maybe this is just a failure of testing, but I don’t think it indicates a widespread assumption among the public that animals are emotionless drones.