Continuity mistake: In the scene where Grug is chasing after Guy, they both wind up stuck in a tar pit. After successfully escaping they are covered in tar and Grug even gets himself stuck to Guy. In the next scene everyone is running from the exploding ground up between the mountains and both Grug and Guy are completely clean and free of tar.Daniel Gauthier
Continuity mistake: When Epe meets Guy, at the fire for the first time, she throws a big rock at him. He yells in pain, and you can see his leg is pinned. But as she picks him up and sniffs at him, the rock is two or three feet away. Even if the rock rolled off his leg, it was way to heavy to lift him up with no effort at all.Hermias Nieuwoudt
Continuity mistake: At several points in the film the mountain is further away from the Croods' position even after they are obviously closer to it then when they started.
Continuity mistake: When the family reaches the lake where they are swimming there is no visible land mass in the background even though they are supposed to be just a few miles from the mountain.
Continuity mistake: In the scene just after the popcorn falls on them, Epe picks Guy up. As Grug speaks to Epe, look at his feet, there's nothing but ground. After Epe explains what if the birds came back, and Gran enters the scene, the camara shows Grug with the log behind him, at his feet.Hermias Nieuwoudt
Continuity mistake: Gran's excessive body hair completely disappears after we see it the first time.
Other mistake: The head of the animal that Guy is wearing when he first meets Eep is not positioned in a way that he would be able to see out of it when he holds his hands up to defend himself.