“What is a snake’s favorite subject at school?”/“Hiss-tory.”

A snake riddle is:
 
Q: What is a snake’s favorite subject at school?
A: Hiss-tory.
 
The riddle has been cited in print since at least 1990.
 
       
14 November 1990, Lansing (MI) State Journal, pg. 8E, col. 5:
What is a snake’s favorite subject?
Hiss-tory.
 
22 July 1992, Vancouver (BC) Sun, “Make your own summer excitement” by Kelly DeGarmo, pg. C7:
Q: What is the first thing a little snake learns in school?
A: Hiss-tory.
   
8 August 1993, The Gazette (Montreal, Quebec), Cecelia McGuire column, pg. A2:
What is a snake’s favorite school subject?
Hiss-tory.
 
Google Books
696 Silly School Jokes & Riddles
By Joseph Rosenbloom
New York, NY: Sterling Publishing Company, Inc.
2003
Pg. 5:
What is the first thing a little snake learns in school?
Hiss-tory.
 
Twitter
Bollywood Sargam‏
@bollywoodsargam
Snake jokes - 8720 Joke: What subject are snakes good at school ?
Hiss-tory ! .... http://tinyurl.com/n8r2zg
5:08 PM - 3 Jul 2009
 
Google Books
The Happy Classroom:
From Ha-Ha to A-Ha
By Janet Aaker Smith
Marion, IL: Pieces of Learning
2011
Pg. 84:
What does a snake learn in school? Hiss-tory.
 
Google Books
School Jokes
By Hugh Moore
Minneapolis, MN: Abdo Publishing
2016
Pg. 12:
What is a snake’s favorite subject?
Hiss-tory.
   
Twitter
Lucky Score‏
@LuckyScoreNet
What subject are snakes good at school ?
Hiss-tory !
#Joke from #SnakeJokes in #Jokes,  #Humor and #Satire
3:56 PM - 30 Aug 2017