You need to establish in your mind that this movie is a pure fantasy fable made for kids because this movie is full of jarring implausabilities that obliterated whatever cool cred it aims to garner. Many key scenes will make you roll your eyes and the set up to the long , drawn out final third act is absolutely impossible. Doesn’t matter if our main character is a pre historic man or not. I wouldn’t recommend this movie because there are other movies from this genre that are much superior in terms of storyline and CGI special effects. One obvious example is 10000 BC, albeit being a mediocre film itself.