At our local zoo, there are several playground areas within the zoo. I am sure that is because most kids act like the Pixel kids. When we went to the zoo, our own kids would run and climb and bounce around. Even at home, we affectionately refer to them as monkeys for their silliness. This strip is more of a terms of endearment than anything.
That said, the joke in the third panel came to me at the 11th hour. I do think it adds a special charm to this strip.
