Why do humans in "Madagascar" have 4 fingers and a thumb on each hand while on "All Hail King Julien" they have 3?
Officially, we don't have any answers (not yet at least). But from what I know, animators tend to reduce the amount of fingers to the least amount possible when animating, to reduce the time, cost, energy, and whatnot when animating each fingers.
By removing one finger, they can save a lot of time, from the process of 3D modelling, and all the way to the shading and other final touches. Usually they make it 4 fingers, as that is the least amount that they can make without making the characters look weird. But as AHKJ doesn't have much human appearances and I suppose you are referring to S3E7/Close Encounters of the Mort Kind, so they do not need to make the fourth finger and it won't really matter. I mean, I never realised that they only have three fingers before this. But as for the lemurs and other animals, they need four fingers as they all play somewhat a prominent role in the story.
I hope I answered your question, but again, this isn't an official answer but just what I think the reason is based on my knowledge ^^;
Wait WHAT?? When do they show humans in All Hail King Julien?
It was in S3E7 (Close Encounters of the Mort Kind). The humans had no lines whatsoever however.
Do you have a picture showing that?
Here's a screenshot from that episode.
Really? Wow, that's sorta weird. But Maurice always has 5 fingers, doesn't he?
Yes he does. I am not sure for sure, but I think it is because he is the chosen one, a.k.a. the most beautiful child. So that might be the reason why.
Timo has 5 fingers too!
Oooh that is interesting! I never noticed that...
What do you think?