I remember reading an article a few years ago that llamas made better herd guardians than dogs. As I recall the article had to do with a sheep rancher who preferred them because of their protective instincts and fearless response to threats. They also require less maintenance than herd dogs.
There are a few ranchers here in Nevada, especially in the north, that use them to protect their sheep herds.
A formal study was conducted by Iowa State University, published back in 1994 when llamas were still a rather new thing in the US. Without any special screening of llama placement by strong guarding instincts, i.e., pretty much random llamas without any knowledge of what makes a good guard llama or how best to deploy them, still resulted in quite dramatic findings. Predation of sheep, mostly from coyotes and dogs, went from an average 11% of the herd per year down to only 1% of the herd per year. Over half of the sheep ranchers reported zero losses afterwards.
One startling fact to me was the observation that 50% of guard dogs did not survive beyond age 3. I wouldn't have guessed their mortality was that high. The llamas, adult at age 4, typically lasted 10-15 years. Their point was that llamas at the time were more expensive to obtain up front but over the long term were considerably more cost effective.
The typical llama strategy when observing a potential threat is to put the sheep in a safe place, then confront the threat by charging it. The typical coyote or dog seeing a large animal running at them will wisely not stick around to see what happens and that's usually all it takes. Llamas have been known to kill coyotes that got too close to the sheep, which they do by ramming, kicking and stomping, but mostly they are diligent sentries, confrontational and smart. Where they get into serious trouble is with packs, wildcats and bear.
Scott
