Colonies of feral cats do better than dogs, especially when they're helped by tenders who provide food, and trap and neuter them to prevent more litters. But everyone agrees that when a pet cat is let loose and can't find a colony or isn't allowed into one, it doesn't have a good chance of surviving more than a few days or weeks. No one knows how many dogs and cats are dying a slow death on their own out there. But experts believe they're in the millions and growing because owners are setting pets free instead of taking them to a shelter.
Some of the owners who leave behind or set loose pets seem to have the idea that since dogs and cats were once wild, they'll quickly recover their survival skills and live a long, happy life running free. Problem is, it just doesn't happen that way. House pets had their wildness and most of their instincts for surviving on their own bred out of them generations ago.
They're always hungry, they're preyed upon regularly, they live in constant confusion about their past/present life, and they're scared most of the time.