Reply #31: Considering that "freak out" rather than aggression is often the cause,

[Gormy Cuss]

I wish more people would grasp dog psychology before they bring home Rover.
Little kids and dogs, not a great combo. Kids on wheeled toys, dog bait.
There are also breeds know to have characteristics that make them inclined to react swiftly and viciously to a perceived threat. The big dogs are just more likely to kill or severely maim when they freak out. Too few owners really take the time to understand what motivates a dog's behavior. "My dog doesn't bite" is not the first thing to think when Spot is growling at a passerby.

In the San Francisco case the dog behaviorists identified several stressors that may have tipped the dogs over the edge. Their Alpha adult had been gone for two weeks, their home was in chaos (the family's belongings were boxed up for a pending move to another state where the father had already relocated), and the bitch was in heat. I don't blame the parents for failing to recognize this unusual confluence of events. It's not as if they chained the beasts in the backyard and ignored them. They just did not recognize how stressed out the animals were, in all likelihood because they were stressed out themselves. It is just a very sad case.