Not the best example, dogs can be converted back into wolves, they can even interbreed with them, Plug-and-Play, so to speak. Dogs are basically domesticated wolves... leave them on the street and they start forming packs, breed like crazy, and sooner rather than later you get weird-looking wolves running around eating smaller animals and bullying everyone and everything. Pack animals are bullies. And if you ever meet a pack of wolves face-to-face (or just one hungry one), you'd probably feel like an endangered animal yourself. That's why in Alaska people have guns with them at all times.

Chimpanzees are the worst, there's a huge population over the world, and they're really violent.