Caveman (1981)

"Back when you had to beat it before you could eat it..."

Disgraced and cast out of his tribe for lusting after Lana, the mate of the tribe's head muscle man, Atouk stumbles along gathering other misfits and learning a bit about the world outside of his cave. Eventually he and friends Lar and Tala learn the secrets of fire, cooked meat, and how to defend themselves from the brutal, yet very stupid dinosaurs.