Headscratchers / Early Man

• Why does the Chief have grey hair if he's only 32? I can understand that cavemen might have died before their time because the world was more dangerous back when we were less advanced, but why would he go grey early?
  • For laughs, probably.
  • Likely because cavemen had a shorter life expectancy in general, even without the dangerous environment.
    • So intentional misunderstanding of statistics for comedy?
  • It could also just be that stress causes him to age prematurely from a hard life, or he might just have hair that turned white 'early'.