Is it obvious I primarily watched cartoons while I was growing up?
What they tell you to do, should you be wandering around the neighborhood and see a mountain lion, is make yourself seem really big. This is typical advice for most encounters with wild animals...that they make themselves look bigger in order to show superiority (typical don't fuck with me posture). Not sure how this would work on a mountain lion exactly seeing as, minus the whole quadraped posture, the average one is about the same size as the average human; length to height wise.
I suspect that you're supposed to make a significant amount of noise along with the fluffing yourself up.
I'm a little sketchy on how effective this strategy is though. Anyone that has any experience with the typical housecat, be they own one or just know people they visit that have them, being bigger is not all that effective. Most domestic cats are not owned by their owners...it's the other way around. All housecats gradually train their owners to be exactly as they need them to be and being bigger affords the human no protection whatsoever.
Think about it: people that own dogs have them poop outside of their homes while people that "own" cats (yeah right) buy things to allow the cat to poop inside.
Is there really any doubt who's owning whom here?
Bit off topic there. The point is, being bigger than a housecat doesn't make a person anymore safe from them so I don't see how making a larger presence of yourself is going to stave off a cat that's about the same size as you and outweighs you as a mass of solid muscle. However, having experience with a housecat can prepare you to deal with its much larger outdoor cousin.
You just need a really big ball of yarn and you're golden!