“What did the bunny say when he had only thistles to eat?”/“Thistle have to do!”

An animal riddle (frequently told at Easter) is:
 
Q: What did the bunny say when he had only thistles to east?
A: “Thistle have to do!”
   
The “thistle” pun has been cited in print since at least 1984.
 
       
Google Books
Mik Brown’s Joke Book
By Mik Brown
New York, NY: Warwick Press
1987, ©1984
Pg. ?:
What did the hungry donkey say when it only had thistles to eat?
“Thistle have to do.”
 
24 December 1997, The Sun (London, UK), “Your Xmas crackers,” pg. 6:
What did the goat say when he only had thistles to eat?
Thistle have to do!
 
Google Books
Giggles, Gags & Groaners
By Joseph Rosenbloom
New York, NY: Sterling Publishing Company, Inc.
2005
Pg. 26:
What did the cow say when it had nothing to eat but a thistle?
“Thistle have to do.”
   
Google Books
Penguin Pocket Jokes
By David Pickering    
London, UK: Penguin Books
2006
Pg. ?:
What did the hungry donkey say when it had only thistles to eat?
‘Thistle have to do.’
   
Google Books
The Mammoth Book of Really Silly Jokes
Edited by Geoff Tibballs
London, UK: Constable & Robinson Ltd
2011
Pg. 336:
What did the rabbit say when he found he only had a thistle to eat?
Thistle have to do.
 
Twitter
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What did the bunny say when he only had
thistles to eat?
Thistle have to do!
#Joke from #RabbitJokes in #Jokes,  #Humor and #Satire
7:56 PM - 6 Aug 2017