Hmmm... that's a really interesting question. I would think in most cases you would have a gun or some sort of firearm.

However, if you do happen to get mauled down by a cougar or deer your best bet is not the largest knife on you, but the smallest.

If you're not being overtaken by an animal but there is one 10 ft away from you then the best thing is to scare it off (i.e. with cougars, make noise and throw stuff at it). If it's a bear and you go into the fetal position and it starts gnawing on your arm then pulling a small little blade could be a handy.

In that case, something that is quick access and tough.

I'd say a Mean Street or a Street Scrapper 4. The HRLM is good, but I think it's a little too big. No actually, the larger handles give a really good purchase so yea the HRLM as well. All of these would be in good kydex sheath in carried on neck, belt, IWB, some where were you could naturally grab the knife.

There are a bunch of smaller Busse Kin knife that would fit the bill. Honestly, I hope you don't get into a situation like that. If there are viscous animals in the vicinity the best thing is to get out and leave them alone.

But you did post in the correct area and this is an interesting question. I'm sure other dawgs, who are more adept at answering this question, hunters, etc., will help.