Regarding using a trekking pole for animal protection.. I know what your saying.. but a sharp carbide tip to the eye would do wonders in convincing a dog or whoever to leave you alone.
I used a prized wooden staff for years while scoffing at those hi techy alum poles. ..until I tried a set. Now I HAVE to have them to backpack. So so so sooooooooooo much more superior. Lighter to carry and wield. More grip at the tip. Infinitely more stable during slick moss covered mtn river crossings, descending, climbing, ice and snow, etc. Also saves a measurable amt of energy, since if one uses the straps CORRECTLY, you don't even have to grip the pole each time they plant it. The strap is always there preloaded and ready to take up the slack, so to speak.
WRONG! The strap is useless in this fashion.
Correct way. Makes all the diff in the world. The only thing the hand(fingers actually) does is direct the pole. To easily throw the tip outward(hold the poles out in front of you..not out on sides of you like a staff), just put pressure on that middle finger riser and the pole shoots out forward. You don't even move the wrist/arm.
http://www.trailspace.com/articles/trekking-poles-fit-maintain.html
If you've got bad knees(like I do), then a set of poles are for you. Especially while going down. Makes the diff between being able to backpack..or not. Just hang out at Neels Gap on the AT(aprox 40 miles from the start) during the Spring. Besides mailing a chitload of crap hikers don't need or use..they sell a ton of trekking poles. Otherwise, many would be going home at that moment because by then its clear if they can continue or not, regarding their knees.
I personally like the spring loaded style, but that's a personal choice. They take out most of the shock to ones elbows/etc on the descents.