Bree does this quirky thing which I call "happy fits". She will be lying on the floor or couch, or even on her own in the bedroom, when her tail starts wagging, then she starts talking and then she starts barking. All the while the tail is wagging and she is awake. There is no provocation, she is lying by herself.
Xena's version is out of the blue while lying on the couch or chair, she starts making snorting noises, shaking her head and grinning while trying to find something to grab hold of like the couch cover.
Lockie so far is "just" happy
Another thing that Bree does is make empathetic howling noises if something sounds distressed. When Lockie used to cry in his crate she would howl softly in return and the other night while the cat was howling (sounded like it was dying) Bere responded by softly howling back. It is almost like lowing? (as in cattle)
Just curious