Realistically, most dogs do not have the strength to defeat a wolf, let alone the courage to confront one. Mastiffs and Bulldogs have been used in the past by wolf-hunters to find and challenge wolves, but they've never been used to actually kill them; the humans used their guns for that. Then came along the Irish wolfhound, bred to be a mix of swiftness, agility, intelligence, and some strength. These dogs were used to find, pursue, and attack wolves before their owners made it to the scene, but even still, Wolfhounds were selectively bred to be swift enough to dodge the deadly snaps of the wolves, not to deal much more damage than a few bites and tugs. A Greyhound could also out-run a wolf, and a well-trained one (for racing, perhaps) could quite effortlessly, but in a confined space with no place to run, the wolf wins hands down.
In short, it is quite a rarity (one that you almost never hear about) that a dog overpowers a wolf by sheer strength.
In short, it is quite a rarity (one that you almost never hear about) that a dog overpowers a wolf by sheer strength.
