Animating Talking Animals ...

Hey...

I can dimly remember once seeing a documentary about how they made the animals talk in Dr. Dolittle.
Searched for it online, without any result so far...

There's also a Non-Smoking Campaign that introduces a similar effect:

youtube: watch?v=IKbxMIWCto0
(no propaganda intended)

So what I was wondering: how do the people behind those projects create believable, fully convincing talking animals?
Do they fully recreate 3D models of these animals and then animating them -- or do they just add some After Effects treatment; something like this:

youtube: watch?v=gKZnL0RhziM

Thanks,
me.

I would assume that most of the jaw motions are sampled from countless clips of those animals. If you look at any movie from the 90s or later you can tell that the lips are tweened with most likely aftereffects