Take a large sturdy walking staff. It'll already be in your hands when you need it.
As far as a knife, I'd actually take a sharpened spike of some kind or a very narrow dagger like a Fairbairn-Sykes http://en.wikipedia.org/wiki/Fairbairn-Sykes_fighting_knife. I don't know how tough their skin is but a slicing cut or chop may not penetrate it. A sharpened spike or narrow dagger is more likely to create sufficiently lethal puncture wounds.
I was going to make a walking staff from a piece of bamboo but a friend told me that ratan is a better material for this application. I'll just need to find a ratan long enough for this staff. It'll also have a small but sharp metal tip.
I agree, the dagger is probably the best for this task, but I don't have one at the moment. So for this trip, I can bring either a large golok or a Busse BM, most likely the later.
Thanks for your comments... :thumbup: