Skip… I just got out the soapbox... if you like.
Actually, the issue isn't always socialization. Talk to pitbull breeders, go on pitbull boards. Pit bulls are bred to be totally animal aggressive. While the AKC dogs have been bred to decrease this trait, the PB breeders brag about it, brag how you wouldn't have a pack of pit bulls because the would kill each other, etc. Don't get me wrong, I know and love many pit bulls. But they are owned by responsible KNOWLEDGEABLE people who have them confined where they cannot get lose, they watch for any signs of aggression in the home, they crate when they are not home EVERY SINGLE TIME, no exceptions, no matter how nice their dogs have acted together. Because if you hang out on a pit bull board (I used to moderate one on AOL), you know that every month, sometimes weekly, new people appear crying their pit bull was always SOOOOO nice to their other dog/cat/whatever, and then suddenly killed it. We see it in as young as a year and I have seen many that were 4 and 5.
I blame the breeders for not addressing the animal aggression, for holding on to "that's what they were made for" idea and ignoring that it is what makes them banned, euthanized and feared. The breeders of American Staffordshire Terriers have worked hard for over 50 years to curb the animal aggression. Pitbull's "respected" breeders brag they work to increase it. Yet, I will say these same "respected" APBT breeders are ruthless in removing human aggressive dogs, and sadly the public gets all these dog bites from poorly bred Pits and pit mixes and anything that might possibly be a pit getting labeled as such. According to the "respected" APBT breeders, a pit bull should be highly animal aggressive and utterly not so with people. Those dogs, kept safe, are wonderful.
So here is why I waded into this thread. Dearest fellow basenji lovers, we have similar issues. Our luck is our dogs are typically under 30 pounds. Imagine, those of you with several and running 2 or more packs due to aggression issues, if they weighed in at 60 pounds. How many could you keep? Our small gene pool makes eliminating dogs with high inter-dog aggression probably not feasible at this point… but I assure you that is precisely why I titled and spayed Sayblee. I have never loved a dog more, and I have known more animal aggressive predatory dogs. However lovely her head or pedigree or speed of finishing... she didn't need to reproduce.
So... look at the Wimauma dogs. They lived in a field in a huge freaking pack. I wish to hell someone had been observing for years. I wonder if the dog aggressive ones got killed and that is why this pack as a whole seems so very nonaggressive to each other? No I am not supporting breeding or cloning the Wimauma dogs :)... but their ability for adults to coexists indicates it really could be beneficial to concentrate on removing the more dog aggressive and maybe start fixing the "it works til it doesn't" issue.