Even as the Rhino breaks the fourth wall in the middle panel, looking back at us in classic Ferris Bueller style seeming to ask the question we are all asking (where the hell does this go and how does it connect to Dirty Dyer?)
At any rate, it’s all putting Frank off his feed, so to speak, to the point that he plans to make a miraculous recovery from a feigned illness and actually go to work!
The Daily Trail 
I think this also begs the question: What in hell is Frank doing boating to the shore where a wild rhino is standing? Is that something a normal person would do? And is Frank on the shore at this point or just sitting in his beached fishing cruiser?
Maybe it was Dirty who broke loose all of these animals to cause havoc in Lost Forest.