>> As far as I know, there still hasn't been a single documented case of a healthy wolf killing a human unprovoked.
"Documented" I'll agree with- in that there is little hard scientific data described. But "witnessed" or "reliably reported"- there are many. (I would propose that being hungry does not make a wolf "unhealthy".)
I'm a big wolf fan, so don't go thinking I'm one of those irrational ranchers who want to wipe them off the face of the Earth, but google Kenton Carnegie. There is some dispute about if it was wolves that killed him, but it seems at least reasonably likely. Scientific data seems equivocal about bear vs wolf; witness testimony seems to favor wolf.
And I think you need to qualify "an ADULT human". I think that wolf predation upon children is rather well known in Central Asia and India. Heck, I think it's been published about in scientific journals. I'm admittedly not so sure of adults, though.
Yeah, here's a mention. Read the fourth from the last paragraph:
Wikipedia also has a page on wolf attacks on humans, but obviously Wikipedia isn't exactly a primo source. Still, reading some of the cites makes it obvious that witnessed and reliably reported attacks by healthy wolves on adult humans DO occur. Read the one about the homeless guy in Iran.
I just think it is silly to assume that a pack hunter that evolved to kill prey in the same weight range as humans isn't going to have at one, occasionally. Such rare outliers are nigh a statistical certainty, given a long enough timespan. Undoubtedly, the vast majority of wolves are well conditioned to fear humans, but more and more are going to become habituated as the human race continues to ooze out across the landscape into their habitat. (Unless we kill them off, which would be a tragedy and a crime.) I want bears and wolves in MY wildernesses...