They really didn't discuss the feeding and watering requirements. "Survivor Man" did an episode with a couple horses and think he concluded taking care of their needs was more trouble than he expected.
from article said:
Bears tend to avoid campsites with llamas. When threatening wildlife approaches, llamas sound a piercing alarm cry.
If I'm going to trek with an animal, I want it to be a Yak. Mostly because I want to climb up something very tall in another part of the world where Yaks are, rather than because I want to hike with a Yak.