Revealing mistake: After Evolet got hit by the arrow and presumably dies, D'leh is staring at a mammoth. Behind the mammoth, you can see that the background is a picture.
Continuity mistake: When D'leh is talking to the Egyptian "god", he walks up to the army of Egyptians. He walks to within arm's length of them, but in the next shot, he's several paces back.
Revealing mistake: In the scene where D'Leh is chasing deer across an open plain, there is a row of 4 to 6 cars with headlights on in the distance coming down a gentle slope.
Other mistake: When the camera pans down from the sphinx there are two flames. You can clearly see that it is a reversed shot by the way they move. (01:15:35)
Continuity mistake: When De'Leh goes into Tic Tic's tent with the white spear and stands, he holds the spear at his side. It jump cuts to a different angle when Tick Tick turns to ask what he wants and De'Leh's stance and position make a very noticeable change.
Factual error: The "corn" they are growing is not corn, just crabgrass.
Continuity mistake: When the 'four-legged demons' catch Evolet leaving objects along the way for D'Leh and others to follow the captives, the leader punishes her by whipping her hands. From behind, two locks of her hair are hanging in front of her right shoulder. In the front shots, four locks are visible in front of the same shoulder. (00:29:35)
Answer: It is explained that he decided not to wait for the last hunt and left to find another way to feed the tribe. He left in secret so that others would not follow him abandoning the tribe.