Around here, (in central Indiana) “a wild hare (or hair)” is an expression that means an impulsive, crazy pursuit, such as driving an hour each way to get a bowl of spicy stew at the Mousetrap or leaving work in the middle of 3rd shift to go fishing 80 miles away. Anyway, there are two ways to say it. Either “he went off on a wild hare,” which suggests suddenly following a long-eared critter, or “he got a wild hair up his ass,” which suggests leaping up from personal discomfort.
Is either of these versions “correct?” Does one predate the other? Do folks even say that in your neck of the woods?
Well, not much luck on Google, Merriam Webster, Roger’s Profanisaurus (but it is a fun site to check!), the Word Detective, or the Maven’s Word of the Day. I tried Bartleby.com and found references to “mad as a marsh (or march) hare”, but the link between that and “wild hare” are clear from that site. Then there’s the reggae club near Wrigley Field in Chicago, The Wild Hare, but that’s another story…
I always assumed it was “Wild Hair” - as in wild hair up his ass - meaning acting all fidgety, etc. as though you had a wild…well, you get the idea, but I couldn’t track down a reference.
That’s all for now - oh, I didn’t search the SDMB yet, 'cuz it’s so darn slow this time of day…
“Hare” exists as a verb, such as to hare around; to run around like a hare. Perhaps the Indiana expression “off on a wild hare” is a case of a noun being made from a verb that was made from a noun, if you get my drift.
I always thought the phrase was wild TEAR. Dictionary.com gives one definition of tear as to move with heedless speed; rush headlong. It also has a slang definition of a carousal; a spree. Too, it lists the phrase tear around and defines that as to move about in excited, often angry haste. To lead a wild life. I’ve never heard the phrase wild hair or hare. Is it possible that this phrase was misheard?
I was raised in N. Florida in the 1960s & 1970s, and distinctly recall “wild hare” being used in the phrase “going off on a wild hare” or “going off on a wild hare expedition”. This could well be a reference to Alice in Wonderland’s following the White Rabbit We used it to refer to going on impulsive jaunts just for the heck of it.
My father, who hailed from Central New York State (and whose grandfather moved from Minnesota in the late 1800s), used the phrases “go off on a wild tear” and “had a wild hair up his ass”.
"To be clear, that’s the pronunciation of “tear” that rhymes with “hare”, not the one that rhymes with “deer”.
By his usage, to go off on a wild tear was to engage in frenzied activity, while having a wild hair up your ass was to engage in work to no obvious purpose. Like ordering a vacuum cleaner, extra bags, and a bunch of cleaning supplies from Amazon might be a wild tear, but reading 15 different webpages on ancient roman shipbuilding is more likely the result of a wild hair.
Since WWII is mentioned, my father was 10 when it ended, so he may have picked the phrase up from young men when he was a teenager.
A Baby Boomer from Toledo, Ohio, I’d always heard this as “getting (or having) a wild hair up (his) ass” among our elders, which my contemporaries and I shortened to “getting a wild hair.” The expression described someone abruptly pursuing an odd or risky course without apparent forethought: He got this wild hair and, next thing ya’ know, he’s a marine. The precipitous action was analogous to the unseemly behaviors one might use attempting to relieve a sudden rectal itch. I considered “wild hare” in this idiom to be one more of the homophone variances, e.g., butt naked for buck naked, which seem more common as they’re shared on the internet. Then again, language is dynamic.