I have read it dozens of times, Cats only meow to humans. My cats are apparently unaware of this, because they meow to each other often. Am I the only one? Do your cats meow to each other?
Baby Girl will let out that same sound whenever we're getting the cats food around. She'll guard us and lash out with an annoyed sounding noise whenever one of the other cats get too close to us. Who needs a trained Rottweiler to guard you when you have a 7 pound tortie.Mine call out to no one once in a while when they're walking around the house. I'm not sure what they're crying about. Sometimes they stop if I meow back. Maybe they're looking for me?
Other than that, one will let out an annoyed "Waaah!" when play gets a little rough between them.