Corrected entry: In the scene right before the carnivorous plant scene, Ellie says, "Hold on". The camera then switches to Manny, and you can see Crash, Eddie, and Diego walking in the background. However, if you look to the right of Diego, you can also see Buck, even though he hadn't joined the group yet. He then disappears from them until the time he's supposed to appear. Perhaps maybe he was originally going to join the herd in his first appearance?