Like most idioms in your first language, the meaning of this one seems obvious: “You and I have a score to settle.” But why does it mean that? Why a zero-sum-game power-struggle vibe, rather than, “Oh, look! I’ve brought a bone that we can share, cuz I’m an altruistic mammal.” [See this week’s NYTimes Science section, for a heart-warming University of Chicago study of (relatively) “free” rats liberating caged rats, even if they did not then get to enjoy the newly-freed rats’ company. They even saved and shared their chocolates with their less fortunate brethren, like something out of a Festive Seasonal Disney flick.]
My extensive collection of Word & Phrase Origin books shed no light on the (bone) subject, so I ventured into [onto?] the web, where I found a site (Usingenglish.com) intended for the wising up of those for whom English is a second language. Mint, nar’mean? They don’t bother with derivations, just plug & chug [“This means that. Just memorize it, already.”] definitions. Other sites attempting to explain whence cometh the bone-to-pick-with-you idiom get all vague and say “Dating from the 15th or 16th century. Referring to two dogs fighting over a bone. See bone of contention.”
So, what? Before the 1400s, English dogs behaved with ratlike altruism and shared their bones? I should cocoa! [Try finding the derivation of that idiom, I dare ya. I’ve been looking ever since I first heard it used in Ealing Studios comedies, in the (19)60s.] Then came the reign of the Tudors, and the Great Bone Panic. [I just made that up. Use of the Poetic speech function.]
And thus, to the bone I have to pick with the NYTimes science reporter, Sindya N. Bhanoo. As with most attributions of species-wide behavioral traits [including the sweetie-sharing rats of Chicago], there is the danger of extrapolating beyond the data. I suspect, for instance, that the “altruism” of the lab rats [which was found more consistently in the females, incidentally] is another manifestation of the Oxytocin effect, in which In-group members are tended & defended, whereas Out-group members [street rats, for instance], would receive short shrift.
Likewise, the Tudor dogs who were observed [proverbially] contending over bones may have been those indolent little hand-fed ones who hung around Hampton Court Palace [not the noble Big Dogs who went out with the hunting parties, and could forage bones galore out in the woods].
Alas, the thoroughly modern Lili is only allowed stage prop Nylabones, which she nevertheless seems to value highly, since she usually tries to pick [gnaw] two of them at once.