I don't know why I haven't noticed till now, my game doesn't use the animated zombie textures. I don't suppose anyone might know why not?
MC version 1.7.10
Optifine U C1 installed
I'm guessing animated mob support was removed at some point? I ask because I'm trying to animate a mob for a mod and all I get is garbled striped mess. Trying to google 'animated mobs' just brings back millions of 3d animated videos (-_-).