Emma has decided to make fun of a weird noise Tuck just made:

E: "When did a horse and a beaver get married?"
T: "I don't know; when DID a horse and a beaver get married?"
E: "It's not a riddle, Tuck! I'm talking about that noise you made! When did a horse and a beaver get married?"
T: "1991"

The conversation degenerated from there...