I'm suprised there are any dogs roaming the streets that haven't been snatched up. Dogfighting is a HUGE problem in the big "D", big enough that organized crime has a hand in it.
CC
Any animal that used to be domestic pets or livestock that have returned to the wild and are seeking their own food sources are considered "feral".
Feral animals are extremely wary of humans and at times hostile to the point of being dangerous to be near unless one has some means of protecting oneself.
This danger facter is especially true in two species, canine and pigs.