When Ryan runs out of the river naked, you can see him bend down to pick up his pants, and just barely you can see that he's wearing blue boxer shorts instead of nothing.
At the end Ryan is shown with the cub, while the camera cuts back twice to show the baby panda still in the jeep with Grandfather Chu.
When Ling is removing her clothes filled with leeches, she is wearing socks. But in the next shot when she enters the river, she is not wearing socks.
After coming out of the river, Ryan's hair and pants are wet, but his jeans jacket is dry.