lion
I guess it matters where you live. If you are in an urban area or sub urban area
where lions are a public nuisance, then you may wish to contact your F & G dept.. If you are in a rural area that is considered normal lion range then that's different. Then F & G's attitude would likely be quite different unless other complaints are coming in from time to time.
For instance lion problems used to be rare in Boise, Idaho 20 years ago, maybe one in town per year each winter. Now it's at least 6 - 8 times per year.
F & G normally will remove them ,often terminally, as they tend to keep coming back, and there is an over population of lions state wide. Lately one lion tried to kill a bicyclist dog as he was riding just above town. It's only a matter of time before a baby gets grabbed in a back yard in my opinion. Dogs disappear often.
Now here in SW Idaho lions are common on the BLM ground and occasionally
show up in the agricultural area from time to time. A neighbor about 1/2 mile away was knocked down and scratched up a bit on his way to the milk barn early one morning in the wee hours a couple years ago. His old dog was Johnny on the spot and shushed him off pretty quickly. We did wonder about the negligence of old spot that morning. That's pretty rare though, and I don't particularly worry about it here at home. We do shut the gate on the pasture when the horses come in about dark, though.
I guess you could pick up a nanny goat or two, if that's an option, and throw them out with your equines. Suspect the lion would go for them first. So if one shows up missing it might give you an advance warning that the culprit is hanging around in the vicinity. Lions are fairly easily trapped if they are in the habit of frequenting an area. About 15 years ago we would catch one about every year now it's 3 or 4. So F & G might be willing to trap your guy if he's caught killing stock (meaning nannys), or attempt it at least, as not all F & G personnel are good cat trappers. In fact few are.
As far as horses being scared of them, I'd guess that depends. These guys here have seen plenty in traps over the years. They always want to get a closer
look each time. So I'd guess they aren't particularly terrified of them. More than once they have laid their ears back and stomped the ground when being spit at. To be sure they wouldn't be so brave if we weren't there. OYE