“What is a frog’s favorite drink?”/“Croak-a-cola.”

A popular children’s riddle about the soft drink Coca-Cola is:
 
Q: What is a frog’s favorite drink?
A: Croak-a-Cola.
 
A “Croak-a-Cola” pun has been cited in print since at least 1978. It was told on the television series The Muppet Show in 1980.
   
“What do frogs drink?”/“Hot croako” and “What is a bear’s favorite drink?”/“Koka-Koala” are similar riddles.
     
           
Google Books
The Crack-A-Joke Book
Harmondsworth, England: Penguin Books
1978
Pg. 155:
What do you get if you cross a frog and a can of cola?
Croak-a-Cola.
 
4 May 1980, The State (Columbia, SC)< "The Divine Miss P Reigns In Lavender Gloves" by Jackie Brooks, pg. 2-G, col. 4:

“Have you heard about the new soft drink they’re making just for frogs? It’s called Croak-a-Cola.”
 
4 April 1982, Newsday (Long Island, NY), “Smiles,” Kidsday, pg. 1, col. 3:
What do you call the new soft drink for frogs?
Croak-a-Cola.
—Stanley Moore, Freeport
 
3 April 1983, The Arizona Republic (Phoenix, AZ), “Students share jokes just for the fun of it,” pg. D8, col. 6:
Do you know what the new soda pop for frogs is called?
No, what’s it called?
Croak-a-cola.
Robert Sonoqual, 11, Sullivan School
 
Google Books
Laughs, Hoots & Giggles
By Joseph Rosenbloom
New York, NY: Sterling Publishing Company
1984
Pg. 78:
What do frogs drink at parties?
Croak-a-Cola.
 
4 November 1987, The Plain Dealer (Cleveland, OH), “Mighty Funny’s Mini Jokes,” The Mini Page, pg. 2, col. 2:
Q: What’s a frog’s favorite drink?
Mighty Funny: Croak-a-Cola.
(Both sent in by Michael Aponte)
 
Google Books
My Summer Vacation Book:
Jokes, puzzles, games, activities, spooky stories, silly songs, and more!
By Stephanie Calmenson and Patrick Girouard
New York, NY: Scholastic Inc.
1997
Pg. 26:
What do frogs like to drink on a hot summer day? Croak-a-cola.
 
Twitter
Prasanna Venkatesh
‏@prazy
Night time PJ - Q:What is the frog’s favourite drink??? A:Croak-a-cola :D 😛
12:23 PM - 7 May 2008
 
Twitter
Ellen DeGeneres
‏@TheEllenShow
What’s a frog’s favorite soda? Croak-a-Cola. #ClassicJokeTuesday
2:47 PM - 13 Aug 2013
 
Google Books
Best Ever Classroom Jokes:
Because some of us never grow up
By Mike Haskins
New York, NY: Pavilion Books
2015
Pg. ?:
What’s a toad’s favourite drink?
Croak-a-cola.