How to rig/animate cat ears?

Those of you with cats will know how their ears kind of fold back against their head when they hiss. I have no idea how to rig ears to do this. Any suggestions?

I suspect you’d want to use shape keys for ears, noses, wrinkles… anything like that.

it depends on how far you wish to go, at the pixar level you would want bones and shape keys. If it was me i would probably add a deform mesh with bones, and use the animall on the deform mesh to fine tune. If you are going to do a lot of animation and the ears bending back in a paticular way i may also add a shape key.

Ok. I need a pretty large range of motion because I think I will be using the ears as the primary way to convey mood. Are there any good tutorials or examples on this kind of thing? I’ve done my fair share of Googling but couldn’t find anything worthwhile.

Basic ear shape for cat is triangular with middle fold running up to the tip of ear. This ridge divides the ear in to two sides;central head or top ear face, and rear side projecting face. When cat moves there ear it hinges up and down from the tip ear face. This face remains mostly rigid. But when cats ear fold back, the rear side projecting face “folds”. So basic rigging will require ear bone for top ear face and second bone to control the fold. Here is one way I added extra bone to control the fold:

Wow. That was very helpful. Now to see if I can get that to work.