I Made It Up.

Although Lewis Carroll did, in fact, write 
The Hunting of the Snark in 1876, his poem
was not the origin of the word.

According to the 
Online Etymology Dictionary,
© 2010 Douglas Harper,
snarky is derived from snark (v.) “to snort” (1866),
from an imitative source akin to
Low German – snarken,
 N.Fris. – snarke,
Swedish – snarka