Reading via mastodon translate a thread by a French poster about recent actions by Macron and partway through got slapped in the face with the discovery that "I'll eat my hat" is an idiom in France as well as America ("Bon, je mange mon chapeau, et c'est pas très bon.")
Is this… how universal is this? Do they eat hats in Germany? Russia? What percentage of earth has a local-language idiom for eating hats?

Census from responses:

Eat hats: English, French, Norwegian, Swedish, Danish*, Icelandic, Hungarian, Finnish, Estonian*, Hebrew

Do not eat hats: German, Russian, Spanish, Italian, Polish, Yiddish, Mandarin Chinese

Contradictory data re: hat-eating: Dutch

* Hat may optionally be "old"

Provisional unified theory of hat-eating (highlighted countries eat hats to express an unlikely event has occured)

The major outstanding question here is whether they eat hats in Estonia*. Is this a universal feature of Uralic languages

* Update: YES

I was supposed to be doing my taxes this morning

It can be dangerous to draw inferences from raw decontextualized data but at this moment, with data from Norway now incorporated, it certainly seems plausible that Scandinavia was ground zero for hat-eating and the trend spread along language affinities from there

Now, you may ask: But then why did hat-eating not catch on among the West Germanic language group? One tentative explanation jumps immediately to mind

This is probably not how etymology actually works
A curveball to my theory! I've just been informed modern Hebrew has an "I will eat my hat" idiom. Now seeking data: Does Yiddish have a "I will eat my hat"?
@nev @mcc ohh I don't know off the top of my head. I don't see an equivalent phrase in any of my dictionaries. When my library stops being under cyber attack I will see if I can search through the ebook New Joys of Yiddish
@ehashman @nev one reason I'm curious is we *don't* find the hat eating idiom in west germanic languages and (Wikipedia says so anyway; I'm outside my area of expertise here) that's the geographical area where Yiddish did most of its development
@mcc @ehashman that said, Yiddish also incorporates plenty of vocab/idioms from Slavic, Baltic, and even Romance languages, so I would not be surprised if there is hat-eating.
@nev @mcc not that there are many digitized Yiddish texts but I did do a quick search for עסן דאס היטל (various conjugations of, literally, eating one's hat) and it came up totally blank :(
@ehashman @mcc עסן די יאַרמלקע?