E-gor's outdone himself with this installment of EGG !
One of the most seamless integrations between real gorillas, and "reel gorillas" prior to Gorillas in the Mist was the 1953 adventure thriller MOGAMBO !
While filming in Africa, the second unit footage featuring real gorillas was directed by legendary stunt man extraordinaire, Yakima Canutt !
Yak carefully integrated the live ape footage ( including some rather pissed off gorillas going on the attack ) with skillfully orchestrated stunt footage of men in very convincing gorilla suits.
The gorillas were attacking star Clarke Gable, who would shoot the rampaging beast while the diving from the brush within just a few feet of him. The inter cuts between real and artificial gorillas was so well edited that it was nearly impossible to detect the change overs.
You can read about more of Yakima's hair raising exploits in his autobiography, STUNT MAN.
I gotta hand it to him, Yak makes one hell of a scary ape !