The sound is generated in the forelegs, most likely by tendon slipping over a carpal bone as weight shifts through the step. It is loud enough to be heard from a considerable distance and is a familiar cue for field observers tracking eland in thick cover.
What makes it interesting is that the frequency scales with body size. Larger, heavier bulls produce lower-pitched clicks, and study of the signal indicates it correlates with dominance rank. A bull approaching a rival advertises his mass before either animal is in view, which allows contests to be settled without a fight. Signals of this kind are hard to fake, since the pitch is set by the physical structure producing it.
Eland are also notable jumpers for their size. Adults clear fences of around two metres from a standstill, which has practical consequences for game fencing. They are among the few large African antelope to have been repeatedly and partly successfully kept as semi-domestic livestock, particularly in southern Africa and the former Soviet Union.