Gorgo said..
It's super fake because it makes no sense at all.
The guy on the bike would have left the bear for dead. All he had to do was hop over the fallen tree and ride away from the bear. All the nature videos of bears show them rooting around and scavenging food and waiting for fish to come for them. They don't chase down prey.
When the guy gets away, "I'll just hide behind a nearby tree. The bear that just chased me for 500 metres won't sniff me out from barely 5 metres away, or see me and my bike sticking out from behind this skinny tree."
OK it's fake but... bears can run really fast when they want, 48 KPH actually and they do attack and kill people, probably about as infrequently as sharks attack, oops.
They have excellent sense of smell but very poor eyesight so if the man was downwind maybe it couldn't find him.
