"It's about Zip," Laddie replied. "Why is Zip like a little boy when he's tired? I mean when Zip is tired. Why is he like a little boy then?"
"'Cause he wants to sit down and rest," answered Russ.
"Nope; that isn't the answer," said Laddie, shaking his head.
"Why isn't it?"
"'Cause it isn't. I know the answer, and it isn't that. Tom helped me think the riddle up. Maybe it's an old one, but Tom said it was good. Why is Zip, when he's tired, like a little boy?"
Russ thought for a while, and then he said:
"I don't know. I give up. Why is he, Laddie?"
"'Cause his breath comes in short pants. You see when Zip is tired his breath is short—he pants, Tom told me. And a little boy, like you and me, Russ, wears short pants. So that's why Zip is like one."
"Oh, I see!" laughed Russ. "That's pretty good. I know a riddle too, Laddie."
"What is it?"