Quote from : Hogfather Book

Yes, sir, but the Librarian likes bananas, sir." "Very nourishin' fruit, Mr Stibbons." "Yes, sir. Although, funnily enough it's not actually a fruit, sir." "Really?" "Yes, sir. Botanically, it's a type of fish, sir. According to my theory it's cladistically associated with the Krullian pipefish, sir, which of course is also yellow and goes around in bunches or shoals." "And lives in trees?" "Well, not usually, sir. The banana is obviously exploiting a new niche." "Good heavens, really? It's a funny thing, but I've never much liked bananas and I've always been a bit suspicious of fish, too. That'd explain it.