Just read WE3 (thanks to comixology's Grant Morrison Vertigo Sales), and cried like a baby.
I don't know why. It's not like the animals (or humans for that matter) had much of a character or that there was much of a plot. It was basically 50 pages of mayhem with a few calm moments in between.
Still, something happened when the SPOILERS SPOILERS SPOILERS dog cries and says it's a "Bad Dog", and when they find home and GOD I'M CRYING AGAIN!
It's... It's and absolutely incredible comics and everyone should check it out.