The film stars Victor Mature as protagonist Tumak, a young caveman who strives to unite the uncivilized Rock Tribe and the peaceful Shell Tribe, Carole Landis as Loana, daughter of the Shell Tribe chief and Tumak's love interest, and Lon Chaney Jr. as Tumak's stern father and leader of the Rock Tribe. Chaney's billing differs from that of his home studio Universal Pictures in that Hal Roach elected to retain the "Jr." instead of billing him under his father's name, possibly because Roach was co-directing the film with his own son Hal Roach Jr..