If animals could speak, the dog would be a blundering outspoken fellow; but the cat would have the rare grace of never saying a word too much.

Mark Twain (1835-1910) American writer [pseud. of Samuel Clemens]

(Misattributed)

This quote is frequently attributed to Twain, but is instead a light paraphrase of the work Philip Gilbert Hamerton, who wrote in his essay "Cats":

If animals could speak as fabulists have feigned, the dog would be a blunt, blundering, outspoken, honest fellow, but the cat would have the rare talent of never saying a word too much.