This is an example of Abraham's jokes....that you will only get if you live in our heads, but are really legitimately funny. In this case, you'll also get it if you've ever read If You Give a Moose a Muffin.
A: "I want to see the geysers!"
S: "Me too. And we can see some animals too."
A: "I want to see the hippos!"
S: "Well, I don't think they have hippos at Yellowstone."
A: "Oh, no."
S: "But they have buffalo."
S: "And deer, and moose..."
A: "And muffins?"