Apparently, a hell of a bullshitter, as well. In a NEW YORKER article, Diamond wrote about the desire to seek vengeance, and illustrated his discussion with an account of a Hatfields-and-McCoys thing in Papua New Guinea. The tribes in question were the Handa and the Ombals, and Diamond spun a real cycle-of-violence tale: a pig wrecks one guy's garden; as the pig belonged to a guy of another tribe, the offended party killed a member of said tribe; and then the nephew of the murdered man set about a three-year campaign of war and attempted assassination to get his revenge, which he achieved when his troops manage to paralyze an important guy in the other tribe. Real blood-n-guts stuff. The kicker is that the nephew, a nice guy in all other respects, cheerfully relishes the suffering and paralysis of the guy he selected to pay for his uncle's death.
And none of it is true. The nephew was never a fighter, he wasn't even related to the uncle, no pig ever went into a garden, and when stinkyjournalism.org sent a guy over to Papua New Guinea to check things out, he saw the guy who'd supposedly been paralyzed walking down the road toting a bag of dirt.
The subjects of the article have now sued. Diamond would have gotten away with this, but he made the mistake of using real people's names. He got away with it for a while, because the NEW YORKER is not a big seller in PNG, but once they found out -- man.
Academic/journalistic fraud is weird stuff. The biggest example I know of is a guy named S. Walter Poulshock, who performed the rather remarkable feat of *making up his entire dissertation.* He referred to imaginary primary source documents, letters that didn't exist, that sort of thing. Best part: when it came out, he was about to be granted tenure at Rutgers.