I’m pretty sure most adult dogs and cats understand mirrors, they just get creeped out by their own reflection. Take an adult cat, hold it up to a mirror. Watch as it actively avoids looking at itself. My dog stares at me for long periods through a full-length bedroom mirror and even barks and runs to the window when she sees dogs outside through it. Doesn’t really care much about her own reflection.
My cat kept meowing at cabinets and mirrors randomly when I was standing near them. After a few days I noticed he was meowing at me, he just was looking straight at me in the reflection, instead of turning around.
I think that was what felisneurologists call “not his moment with the brain cell”.
Nah, it’s me who needed the braincell. He was using the mirror to look straight at me. He knew I was behind him, he wasn’t confused about there being a different person in the mirror. He was too lazy to move his head high to look at me directly, so he kept looking through the mirror so he didn’t have to.
