What excites these dogs?

A few weeks ago, Gwennie and I were at Costco. We were looking at the books, when she saw this one. We picked it up, and she proceeded to rip the head off of one of the dogs inside. Being afraid that some other mom would buy it and get it home before she realized that there was a headless dog inside (which she would totally have to explain to her poor child. "No, honey he had a head but it was taken off, in the book. In real life he had a head!") I purchased said book without much thought. Its been around, we have looked at it, and read the words, but I hadn't really examined all of the pictures.

Today Will told me I needed to look at the last page. I asked him if he was referring to the part of the book that states "All dogs poop, All dogs pee." (with pictures, including one with a pull tab that allows the dog to lift his leg and urinate a bright, yellow stream onto an unsuspecting tree, time and time again.)

"No, look at the back page."
I do, and lift the flap. Where a poor cat is cornered in a tree by many dogs staring up at it greedily. I notice that the cat is named "Kitty, The Calico Cat" even though it is an orange and white tabby. I point at that and say "Yeah that is pretty funny, since it is not a calico cat."
"No, close the flap and look at the tree."
Its no wonder these dogs are excited! Its REEFER MADNESS!