I once owned an English Bull Terrier. That dog crushed a door knob with ease. I was at a breeder near Palm Springs and asked her if she worried about Cougars. She said no, as her dogs were nearly fearless and could easily rip one apart.
Our dog once lit out across the street after a 185 lb. Rottie. I was worried our pooch would get hurt or killed. Fortunately, the dogs got along and later on our vet told me the Bull Terrier would just snap the larger dogs legs and then go for the throat. We had to get rid of ours because he was adopted and was abused prior to coming to us. As such, he trusted no one and would easily bulldog my legs out from under me and go for the throat to dominate and be alpha. He never really hurt me, but I could not take a chance he might harm my family. Never have I seen such an incredibly powerful dog. I gave him a LARGE Nylabone and he easily bit in two. Like a twig.
A Mountain Lion might have a chance. Just once. That dog was incredible and I honestly think he could easily kill one alone. We tried to rescue him but he was too untrusting of people and therefor quite aggressive.
These dogs whilst very keen and aggressive, are very stupid dogs, they will take on just about anything....
Just cause an English bull terrier will take on a mountain lion doesn't mean it wouldn't be mince meat in two seconds flat.... The dog would stand no chance.
