“Why can’t dogs dance?”/“Because they have two left feet.”

A clumsy dancer is said to have “two left feet.” A popular animal riddle (usually about dogs) is:
   
Q: Why can’t dogs (four-legged animals) dance?
A: Because they have two left feet.
 
The riddle has been cited in print since at least 1964, when it was published in Boys’ Life magazine.
 
“Dressage horses dance really well for having two left feet” is another “two left feet” animal joke.
   
       
Google Books
January 1964, Boys’ Life, “Think and Grin,” pg. 58, col. 1:   
Wilson: Why are four-legged animals poor dancers?
Terry: I don’t know. Why?
Wilson: Because they have two left feet. — Howard Watkins, Los Angeles 29, Calif.
 
7 August 1981, The Times-Picayune (New Orleans, LA), “THe Bean Bag,” pg. ?, col. 4:
Q. Why are most animals bad dancers?
A> Because they have two left feet.
   
Google Books
Boys’ Life
1987
Pg. ?
Fred: Why can’t dogs dance?
Ted: I dunno, why?
Fred: ‘Cause they have two left feet. —Vivian McKune, Pittsburg, Calif.
 
Google Groups: rec.pets.dogs.misc
Why are dogs such bad dancers?
Regina M. Seaner
10/24/96
Because they have two left feet!
   
Google Books
The Biggest Ever Joke Book
Bath [UK]: Dempsey Parr
2000
Pg. ?:
Why can’t dogs dance?
Because they’ve got two left feet.
 
Google Groups: alt.humor.puns
Kids Puns of the Weak 10-19-04
Stan Kegel
10/19/04
(...)
Why don’t dogs make good dancers?
Because they have two left feet. (Lee Hogan)
 
Twitter
Tina Dupuy
‏@TinaDupuy
Here’s my clean, kid friendly holiday quip:
My dog can’t dance…she has two left feet…
2:36 PM - 24 Dec 2008
 
Twitter
Mark Ferguson
‏@arkstfan
That horse can’t dance.
How do you know?
He’s got two left feet!
#DixieStampede
8:15 PM - 13 Nov 2009
 
Twitter
Steven Winterburn
‏@5tevenw
I tried to teach my dog to dance, was a waste of time, he has 2 left feet!
11:19 AM - 24 Nov 2009
 
Google Books
More Cool Werewolf Jokes For Kids
By Peter Crumpton
PeteyRF Creative
2015
Pg. ?:
Why don’t werewolves make good dancers?
Because they have two left feet!
   
Google Books
Funny Jokes and Riddles for Children
By Alexandra Cooper
Lulu Publishing (Lulu.com)
2016
Pg. ?:
Why don’t dogs make good dancers?
Because they have two left feet!