Horse & mule packer are not the only ones using back country trails, there are other ways to get your stuff from trail head to great locations in the mountains of Idaho. As stock packers we should know a bit about the other types of pack stock, and how they view us.
Encountering pack stock on a trip from a goat packers point a view is a good example:
(Note: We do not dislike horses per say, any derogatory sounding comments are based solely on personal observations of them and their reactions to us with our goats.)
It is our experience that very few back country users know the answer to this question. Thankfully our boys are familiar with both backpacks on people and horses, so are total unconcerned beyond there natural wilderness alertness. Most hikers hate the idea, but as the most mobile they should get off the trail on the low side. In a goats vs horses the same rule applies. We move to the low side as the goats are much more agile than the horses. (Horses are much easier for the rider to control on the high side of the trail. Move approximately 30 feet off the trail for horses). We have decided that horses think people with packs are bears, and llamas/goats with backs are devils from their darkest nightmares. With horses it is a excellent idea to keep talking to the riders as they pass, as this helps the horse with their tiny little brains identify you as a person rather then a scary unknown.
There are times when passing is not an option. (The east fork of the Duchesne comes to mind. A 1/4 mile, six inch ribbon of trail across a 70 degree slope of loose dirt.) In these situations the most mobile should back up to a safe place to pass.
Pack strings of any sort should be given consideration over any kind of person with a lone creature. But we seldom argue with a spooky horse and just give way. And our boys watch the horse dance fitfully past with silly grins on their faces.
To lean a bit more about goat packing, check out the following web sites: