I’m riding my exercise bike in the basement when the cat shows up at the window (it’s sunny, but around freezing outside).
She meows. I can’t hear her, but I meow back. She sees me, and satisfied, her head drops out of site.
The dog hears all this and comes running.
Now cat and dog are staring at each other through the glass door.
I let the dog out, and the two of them are wandering around the backyard together.
Their pet is, at least, useful.