What distinguishes the zoo from McGrew's beasties? The people visiting the zoo, naturally. McGrew could just have easily have thought up the creatures without gathering them all together in the zoo for others to see. But he didn't. He imagined the visitors and the animals in tandem.
McGrew's Zoo shows yet another beneficial aspect of imagination. Yes, If I Ran the Zoo is the imaginary gift that just keeps on unwrapping itself. This time, the gift is a view of the communal benefits of imagination.
We already hear some of you objecting to this one. Yes, McGrew does share his creations with the zoo's visitors. And, yes, they do think his "zoo [is] better than Noah's whole Ark" (34.9). But, all those people are figments of his imagination as well. McGrew isn't really sharing his creations with anyone, and he's only praising himself.
True. All true. But let's not forget what we learned in our discussion of "Animals." Just because something starts in your head, doesn't mean it has to stay there. McGrew envisions what people will say about his imaginative creatures first. This gains him the confidence to eventually share his creations with others, whether as a story, a book, a piece of art, or maybe just in a passing conversation. The point is, he must use his imagination first before getting to the point where he shares his imaginings with others.
In a way, McGrew is a surrogate for Dr. Seuss himself here. All these animals really did appear within Seuss's head. And he probably imagined what other people would think of them, tweaking and changing them until the people in Seuss's head agreed they were awesome. Hey, this is how artists work. Then, when Seuss was ready, he shared his creations with others, a communal appreciation of one man's imagination.
In a Twilight Zone kind of deal, McGrew's zoo is Seuss's Zoo. And the visitors to McGrew's zoo are the readers—that's us. And wouldn't you know? We gave it all kinds of praise. Consider our minds blown.