Continuity mistake: When Charles Travis picks up the eyeball as he sits on the steps of Zinj, he changes from holding it in his fingers/on his palm. (00:06:50)
Continuity mistake: When Dr. Elliot is doing his presentation, there is a large TV on a stand, with a VCR, which suddenly vanishes halfway through. (00:11:10)
Continuity mistake: When Charles Travis sits on the steps of Zinj, waiting for Jeffrey to get his bag, there are branches to his right, which keep disappearing. (00:06:30)
Continuity mistake: When Homolka has to jump out of the plane, he first sticks his head out the door. The exterior shot shows that his left hand is holding onto the plane but not in the interior shots.
Continuity mistake: After the diamond mines of Zinj are found, Homolka gathers up the diamonds. When he asks Kelly to help, his hands change positions between shots. (01:26:54)
Answer: Seconds after he drops dead, an ape comes from where he'd been running from and throws a human brain at the living humans. This is Richard's brain, torn from his head. In the context of the film and employing a (fair) bit of suspension of disbelief, he must have had enough brain stem (where reflexes are governed) left to run and scream a bit before dropping dead. In reality, of course, this is an extremely unlikely if not impossible scenario, invented by the screenwriter for the purposes of a gruesome death. Perhaps inspired by stories like Mike the Headless Chicken, an animal which survived for months after having most of its head/brain chopped off.
That wasn't a brain that the gorilla threw; it was the head of one of the two porters with whom Richard remained outside the cave.
Phaneron ★