I know we’ve had various discussions about off-leash dogs being dangerous (or at minimum, a nuisance) to runners. In Belgium, a woman let her Jack Russel terrier off-leash, it approached a runner, and the runner grabbed a sharp object out of his waist-pack and stabbed it. He was arrested and had to spend a night in jail. Pretty crazy story. Belgian ultrarunner arrested in bizarre dog-stabbing incident - Canadian Running Magazine Stabbing and killing a dog seems pretty extreme, but the runner was probably prepared for a reason (like bad experiences with unleashed dogs in the past).
A veritable “man bites dog” story. Freaky!
I’ll admit that I’ve sometimes evaluated my options when I’ve been approached by hostile dogs, but I’ve never needed more than a bellow to send them running. Well, except for the time I was riding the ElliptiGO up a hill and was stopped by an aggressive dog (who was showing off for its beta dog) because I couldn’t go by fast enough. I could keep it at bay, but couldn’t get away for quite a while.
I learned a strategy from my younger brother “Spider” that always works, even with street dogs in Ecuador or Brasil. Lean down at the side of the road or path and pick up some loose gravel in your right hand while eyeing the dog. No need to throw it, the dog will turn tail and back off. They do not want gravel in their eyes.