Pumas, Mountain Lions, Tigers, and the like are sneaky animals by the time they are on you 99.99% of the time there is very little the person being attacked can do to defend oneself. Picture your body flopping around... grabbing a knife, unhooking the sheath and using it is probably way out of the question. Reports on such attacks all pretty much say the person attacked had no idea what happened.

I'm def. not against a large knife. One of my favorites is a RAT-7, and for clearing the RTAK. However, 99% of the time I don't have either with me... so a quality folder is a must