Hikers should have turned around and left when

...they encountered the mauled deer.**

Also, although bear spray does send them away, a case in 2016 reported a couple sprayed one, but it came back. Fortunately the bear gave up after encountering the same cloud of spray.

http://www.kbzk.com/story/33480910/bozeman-couple-saved-from-injury-after-using-bear-spray-on-charging-grizzly-in-yellowstone

True bear attacks will raise the hairs on the back of your neck while reading Death in Yellowstone - https://www.amazon.com/Death-Yellowstone-Accidents-Foolhardiness-National/dp/1570980217


While Yellowstone is not in Canada, the advice** for bear protection is valid everywhere.

Quite a harrowing scene where the man was being attacked and eaten. The actor's screams were terrifying.