From a Sterling Holloway stork to a Sterling Holloway snake...
I didn't notice this myself, I had read a very offhand remark about there being two different looks for Kaa in the Disney Jungle Book. So I decided to check it out:
Indeed, in the clip below (his second sequence in the film) he looks much cartoonier than in the clip above (his first sequence). His eyes are closer together and rise further above his head, his nose tapers out the way instead of in the way... and the general shape of his face allows for more variation in movement... actually, in the later sequence he almost looks like a serpentine Daffy Duck, say... mid-1950s, Chuck Jones unit.
The later design is certainly the better of the two, and probably the "definitive" look for the character, but I wonder why the earlier sequence has the different design? A common explanation would be that it had a different animator, but you'd think on a feature film like this they'd have a standard model sheet and diligent assistants to keep the drawings close to that model sheet. Another possibility is that they changed the design after they had already animated the earlier sequence, but surely they'd get someone to reanimate it, like they did with Dopey's soap antics in the washing sequence of Snow White. After Disney's death did consistency really fall apart?
As some people might not know, Woolie Reitherman, the director of The Jungle Book, was very fond of reusing animation. In this case, the scenes of Kaa unravelling (1:56 - 2:07 in the first clip, 4:55 - 5:00 in the second) are the same. This creates a continuity error: when he unravels in the second sequence, the way he's wrapped around the tree branches changes completely. It also makes the difference in the design stand out a bit more.
Oddly enough, some of the following footage in the second sequence is reused from the first sequence, while some is new. But, of course, even in the new footage he still has the (older?) first sequence design.
Oh, and if any of you are turned on by the thought of a ridiculously long snake hypnotising you and coiling himself around you... well, keep it to yourself, OK? ;)