With his neatly trimmed hair and beard, this 'Asian caveman' is made to resemble a chimpanzee. But cavemen didn't have electric hair clippers to cut their head hair and beard in this way.
Scientists have no answer to the question of why humans have long head hair, and why males have long beards. And when scientists can't answer a question, they tend to avoid it, and even try to hide it. This image helps hide that particular question. Paleoanthropologists avoid most of the questions about chimp-human differences.
In his book The Passionate Ape (PassionateApe.com), Craig Hagstrom explains remarkable traits of chimps and humans. He suggests that humans evolved long head hair and males long beards so that infants and young children could hang on while floating in the water. Female children who hung on to the beards of men became accustomed to facing mature males front-to-front. Women who had grown up without fear of mature males tended to have more offspring. Similarly, men who happened to have longer facial hair tended to have more offspring.
This sounds like a 'just-so' story, but I know of no other selection pressures that can explain why humans have long hair in these places. Hagstrom's book is creative, well researched, and beautifully written. It is one of my favorites.