Why are all the tourists, from all the car-jacked jeeps, New Yorkers?
Why does only one group of tourists have a guide and a weapon?
Why don’t they follow the same road/path they took into the preserve to get back to wherever they came from instead of wandering off into the bush, off the preserve (with only one guide and one rifle)? Why are there no communities along the river? Why do the tourists dam the river?
Why does no one come looking for them?
Why doesn’t the lion ask a single question about the rite-of-passage ritual? Why doesn’t the lion take off the funny hat?
You will undoubtedly have noticed that most of the questions above have to do with the human parts of Madagascar 2. I was willing to buy the talking, dancing animals, the genius penguins, and the not-real-never-was-real version of the Central Park Zoo. But once people became part of the story, it was hard to maintain suspension of disbelief. My 12-yo was having the same trouble; at least three of the questions above are hers.
A G-rating is no excuse for a bad story, as Pixar proves fairly consistently.