Snake on Stilts (tall, thin person)

“Snake on stilts” is an old West term for a tall, thin person. Texas was known for its many snakes, and it’s easy to see how it could color the cowboy’s language.
   
   
Old West Insults & Sayings
SKINNY/FAT
He is so thin he could take a bath in a shotgun barrel.
He was so fat, you’d have to throw a diamond hitch to keep him in the saddle.
If he closed one eye he’d look like a needle.
He is so fat, you’d have to throw a diamond hitch to keep him in the saddle.
He is built like a snake on stilts. 
 
Google Books
Cowboy Lingo
by Ramon F. Adams
Boston, MA: Houghton Mifflin Company
1936
Pg. 212:
...“he’s built like a snake on stilts,” “he had to stand twice to make a shadow,” “he’s so narrow he could take a bath in a shotgun barrel,” and “if he closed one eye, he’d look like a needle. 
 
Roundup Recipes
by Bonnie and Ed Peplow
with the help of the Arizona Cowbelles
Cleveland, OH: The World Publishing Company
1951
Pg. 270 (Glossary):
SNAKE ON STILTS: Typical colorful cowboyism for thin.
 
15 November 1952, Tucson (AZ) Daily Citizen, “Where the land is so big it has a voice of its own,” pg. 22:
“If he’s fat, he is “beef plumb to the hocks.” If he’s thin, he is “built like a snake on stilts.”
     
Google Books
The Cowman Says It Salty
by Ramon Frederick Adams
Tucson, AZ: University of Arizona Press
1971
Pg. 144:
Jesse Spillers once said of a thin person that “he’s built like a snake on stilts and has to stand twice to make a shadow”;...
   
14 November 1977, San Antonio (TX) Light, “Talkin’ Like a Cowboy” by Keith Elliott, pg. 2A, col. 2:
TALLNESS. Built like a snake on stilts.