They must remember by smell, maybe? We’ve always wondered.
My dogs (We have 3 Cocker Spaniels)remember my kids who make it home maybe twice a year. The never forgot my Husband after 6 month deployments and they also remember my Mother in law who has visited twice in maybe 3 years.
They greet them like they do when I come home from going to the store. They grab a toy to greet them, whine, run around them, climb up on them then run straight for the kitchen for a doggie treat.
Pets do remember...my MIL’s cat always greeted me with joyful enthusiasm every time we visited, and until he was neutered he didn’t really like anyone. He’d headbutt my face, try to bite my nose (which was the ultimate show of affection from him, reserved only for his MOST favorite ppl), and cuddle up close. I saw him a few times a year but he would go just as nuts after 6 months as if he’d only been shut out for the night.
I miss him :-(