This was a pack of a couple of dogs. Imagine a pack of thirty like they get down in Puerto Rico sometimes or a pack of a couple hundred feral dogs.
All those civilian peacetime dogs on the couch in the pre-attack environment so harmless they wouldn't hurt a fly. Wait until their surviving litters get old enough and numerous enough to basically kill anything they want to whenever they want to.
It's going to be one of the biggest hazards and most people have never really thought about it much. They only think of dogs as man's best friend. The alternative doesn't really occur to them. Without socialization, people and dogs turn into ravenous beasts.
A pack of thousand feral dogs would be scarier than a mob of a thousand zombies in terms of the threat they pose to a man or woman on foot. Dogs, rats and insects will go through boom-bust cycles after the bomb and if you're caught in a boom cycle you'd better be underground or in chainmail.