The fourth Mutts book.
It features the first "shelter stories" about animals awaiting adoption. It also has a sequence about how the guard dog is kept chained up.
Other sequences includes Mooch and Earl tracking a bear -- Mooch yells at it to get out out of the way, it's on their tracks -- and their getting into a boat and ending up at sea -- I particularly like the Sunday one, which shows them talking about being all alone over a sea full of creatures. It also has Mooch posing as the Sphinx for the first time, and a bird who decides walking south is safer than flying.
Some are aiming for the sweet and touching rather than the comic, but it's a good set.