Not only are elk big, extremely strong animals, they have a well-earned reputation for being difficult to take down. Even with a high-powered rifle, perfect shot placement in the vitals is absolutely critical to ensure a clean kill.
Huntley's elk hunt took place in relatively flat country. Thick sagebrush limited his opportunities to take a rest from a sitting or kneeling position. This was an ideal situation to utilize shooting sticks, which provide a good rest when standing.
The standing tripod (left) has a long history with African hunters and provides an extremely solid rest while the monopod (right) is the preferred choice of hunters who need a quicker, albeit less-stable, rest at-the-ready.
For his elk hunt, Huntley found the tripod the more suitable rest given the potential for a long-distance shot and the favorable, level ground. The tripod is far more stable than an off-hand shot, and the height can be easily adjusted to fit the individual shooter.
On solo hunts, Huntley carries his tripod broken-down in his backpack, but Bill offered to carry it for him, fully extended, which allowed Huntley to keep his hands free for a quick shot if they encountered an elk enroute.