As the title: What organs or modifications would be needed to have creature that can eat/digest hair without problem? (Preferably digested normal/quick enough, and they only eat hair.)
This includes other animal fur but if it's impossible then at least human hair, and I know about Trichophagia and hairball.
I want it to be a big creature type, at least as big as a cat or frog, also I don't want it to be insect type.