sorry, B00, I didn't quite put that right - they kill the rivals first. Then they kill the offspring - and that's hardly necessary but they're doing it not just to become leader of the pride, which they've already done, but to eliminate all traces of other males forever. I'm guessing the instincts of these human killers are moving along the same lines, and I'm guessing there is some instinct involved. Just think of all those fairytales involving wicked stepmothers. They represent kids' fears that their mother will die and be replaced by another woman, who'll abuse them in order to promote her own children with their father. I'm not defending these people at all, just saying there's something subconscious going on that overrides what would normally be your natural sympathy for little kids. They can go to jail for a very long time indeed as far as I'm concerned.