But mistakes are made. Surely there will be quite a few rogues hiding out. If you've been in woods, jungles, or swamps in real life, you'll see that places to hide are EVERYWHERE. Perhaps there are enough hiding in dens, adapted to wild life, to cause mass endangerment to wild natural animals.
If wild Rogues kill off anything for food, then natural fauna species can die out before Shaper intervention. Who's to say that Roamers didn't simply kill off their ancestor dogs?
Rotghroths.