Apparently, there might be some examples of the latter in the Interspecies communication thread.

Here, I have voted for both...

Me too!

Anyway, Aria (an Alsatian) communicates in various ways: she 'snaps' her upper and lower jaw very gently in my face: supposedly she's being affectionate. When I do the same to her, she repeats the movement while looking very calm and loving. 

Whenever I let her out in the garden, she does an interesting parameter check: she runs alongside the fence the whole way 'round. With raised hackles and a stiff 'beware' posture, she barks as loud as she can. When she has finished the round, she stops and looks at me. I reinforce this particular communication by loudly approving. Very good!

She smacks her lips loudly when I get annoyed at her. Supposedly it's a way to pacify members of the tribe: calm down, Nanna!

She does the smacking lip thing with her ears pulled way back when I get very wired about the mud she drags in from the by now always wet and muddy garden. To reassure her that she has managed to calm down the alpha, I step away from her and then smack my lips in return: she relaxes, and allows me to clean her huge paws without any fuss.

Nanna 

I basically think that languages are like music: like the ancient rhythm of the drum talking to you in different forms.

Liliana

That's music to my ears.  

I think He thought it was Art.