With the plethora of mysteries in genre, lately, we've seen a lot of red herrings on screen. Were you aware that, for a long time, the origin of the phrase "red herring" was itself a red herring? We'll tell you where the phrase really comes from.
The phrase "red herring" is, in general, a literary term. As readers grew savvy enough to know that any seemingly extraneous person hanging around in the background of a murder mystery (or episode of Law & Order) was inevitably going to be the murderer, and any casually mentioned detail was going to be the one that led to that murderer, it paid to throw in a few confusing clues, leading people towards dead ends. These days, readers and watchers of genre mysteries get a whole school of herrings. From characters that have motivated everyone in their universe to kill them to the possible appearance of pagan gods, we don't know what to make of so many clues.
Where does the term for red herring come from? To begin with, red herrings are herrings that have been smoked so long that they turn dark red. They can be preserved for months - at the cost of being extremely smelly and inedible unless soaked in water. They'd leave quite a trail, for anything with a sensitive nose.
Scholars found the original reference to red herrings was all the way back in 1697, and refers to how to organize a hunt. Trailing a red herring on the ground was recommended for training hounds to follow a scent. As it turned out, this little red herring mention was a red herring. Although the book did mention red herrings as a possible scent, it was just a way to lay down an easy scent for hounds, who knew they weren't chasing anything living. The actual animals being trained were horses - so they wouldn't get spooked later during an actual fox hunt. Not only that, but a red herring was only used if nothing else could be found. The best choice for laying a scent trail, the text insisted, was a dead cat. (Just as an aside - I wonder how different the world would be if this really were the origin of the phrase, and we talked about how a mystery writer led us on with a "dead cat.")
Later, linguists found the actual origin of the phrase - used about a century later. A firebrand journalist, William Cobbett, railed in 1803 against the laziness and foolishness of the rest of the press. To add a little color to his rant, he made up a folksy story about how when he was a child he would draw hounds away from a hunt by trailing a red herring along the ground. The journalists in his time, he said, were just as easily misled. The story caught on, and entered the public imagination. Eventually authors began to metaphorically do what Cobbett (probably only fictionally) did.
[Via World Wide Words.]