Twenty years ago, South Africa's Kruger National Park had too many elephants -- far more than the park could sustain. Game managers came up with a two-prong approach: Relocate some of the herd to Pilanesberg, another game park, and (sadly) kill off some of those too big to transport.

And that, according to a fascinating segment of a recent "60 Minutes II" broadcast, is precisely what happened -- except Bob Simon started his report with a more recent crisis: the unexplained slaughter of white rhinos, an endangered species.

The first thought was that it must be poachers who were responsible for a killing spree that claimed at least 39 white rhinos -- a tenth of the Pilanesberg herd. But that thought was quickly dismissed: The carcasses had their commercially prized horns intact. One theory after another was explored and dismissed until finally game wardens tranquilized and tagged some of the rhinos so they could be more easily tracked. They also set up hidden video cameras.

Here's what they found: Young bull elephants were harassing the rhinos, for no apparent reason -- throwing sticks at them, menacing them, chasing them over great distances, and finally stomping them to death.

Moreover, these now teenage members of the group that had been transported from Kruger were being led by a handful of particularly bad actors. One of these, dubbed Tom Thumb by the rangers, accumulated the game park equivalent of a videotaped rap sheet: several instances of chasing white rhinos, marauding, aggressive interaction with a tourist vehicle. Somehow, Tom Thumb escaped the park marksmen who had to kill five of his out-of-control pals.

Another of the tough young bulls (street gang leaders, the park officials called them) once spent seven straight hours harassing rhinos, and a week later attacked members of the same rhino herd. This young bull -- Maphuto, they had named him, had to be shot. (In a scene evocative of too many inner-city tableaux, Maphuto's young sister refused to leave her fallen brother as other members of the adolescent "gang" ran away.)

According to Bob Simon, the rangers and scientists detected a pattern: The young sexually active bulls, "suffering from an excess of testosterone," were becoming increasingly violent. Indeed, it seemed for a time that more of them might have to be killed.

Then last year someone got the bright idea of bringing some older, mature bulls to Pilanesberg (there was, by then, the technology to transport the bigger animals). Perhaps the bigger, stronger males could rein in the teenagers.

The gamble paid off, for reasons both obvious and subtle. The bigger bulls, establishing the natural hierarchy, became the dominant sexual partners for the females. The resulting reduction in sexual activity on the part of the young bulls also lowered their testosterone levels and reduced their violent behavior.

But it wasn't just a matter of size-based intimidation. The young bulls (after a few early and futile skirmishes with the "Big Daddies") started following the older bulls around -- obviously enjoying the association with the adult males, yielding to their discipline and learning from them proper elephant behavior.

Even the once incorrigible Tom Thumb has stopped harassing the rhinos, and there hasn't been a report of a dead rhino since the experiment began.

Simon's report is a virtual parable for what is happening in America's inner cities. One could, no doubt, find the public policy counterpart of the original separation of the young males from their adult role models: in welfare policies that emancipate teenage parents and render males economically irrelevant; in criminal justice policies and employment policies that have stripped adult men of their normal roles -- but mostly in sincere attempts to help a segment of the urban population without properly understanding the unintended consequences of those attempts.

More important, though, are two other lessons from the Pilanesberg elephants: first, that the absence of responsible adult males -- no matter the cause of that absence -- has serious, even deadly, impact on the younger males and, second, that reintroducing adult males into the community -- whether related to the youngsters or not -- can help powerfully to guide the youngsters into responsible adolescence and adulthood.