More on 'snark' and its origin:
Snark in various forms is common in German and Scandanavian language- to gnash, snort, or snore. It's origin is at least medieval. Found in English writings by the 1860's.
Jamieson's Scottish Dictionary in 1882 defined 'to snark' as 'to fret, grumble, or find fault with someone'.
By the early 1900's snarky was firmly in English, meaning irritable, short-tempered. In the popular "Railway Children," by Nesbit, is found " Don't be snarky, Peter. It isn't our fault."
R. Fay, "Letters," 1912, wrote "So sorry I seem so snarkish just now."

As noted above, another meaning and use of 'snark'- 'Lewis Carroll' gave the name to an imaginary animal (1876).
By 1879, 'snark-hunting' became popular, and quickly entered political commentary.

Defining snarky as 'sarcastic' bends the meaning a bit; not yet found in the OED, but this meaning has entered slang.
Sometimes shortened to 'narky'.