Around 7% of American men say they think they could win an unarmed fight against a grizzly bear. This comes from a 2021 YouGov survey of U.S. adults asking which wild animals respondents believed they could defeat in a bare-handed fight. Grizzly bears ranked among the least winnable matchups. Grizzlies reach sexual maturity around 4–8 years (often ~5–6 for females) and are considered nearly full-grown by 5–8 years, though males continue growing slowly into their teens. A typical adult male is 300-400 lbs. One swipe with their giant claws would rip a man to shreds. Grizzly bear hide is exceptionally thick—often described as up to about 1 inch in key areas like the neck and shoulders—plus a substantial layer of subcutaneous fat that can reach 4 inches or more. Stabbing a grizzly with a pocket knife won't do a thing.

@Martyupnorth No man wins an unarmed fight with a grizzly bear. It is possible the bear gets bored and leaves you alone, but if it sees you as a threat or as food you’re dead. It’s that simple.