Anyone who has owned a dog or cat will at some point ask a crucial question: why on Earth do pets follow you into the bathroom? If you dare shut the door, they often yodel until you open it again, and then patrol the entire bathroom.
According to the scientist cats and dogs have different reasons for hounding you.
When it comes to dogs, the answer, according to experts, has to do with pack behavior. Dogs have evolved to be pack animals with strong bonds to those around them, and in their domesticated state, the instinct to physically stick with the members of the pack transfers to their humans. The dog is expressing loyalty and togetherness, and dogs, like their wolf ancestors, haven’t been bred to understand the idea of “privacy.”
On the flip side cats are not known to be pack animals and their own privacy is paramount.
The cats would because they are insecure and want to check if there is nothing untoward going inside the house which could be threatening to them. Felines are territorial animals and they need to know what’s going on in their environment.
The dogs want to know you’re OK and be wherever you are; the cats resent the closed door and want to check that nothing untoward is going on in their house.