What is suggested to correlate with the sheer size of the *Xenoceratops* frill, beyond display?

Answer

Housing a bulky digestive system for fermentation

The size of the frill might correlate with the requirement to house a correspondingly large gut, necessary to contain microbial fermentation chambers for breaking down tough cellulose.

What is suggested to correlate with the sheer size of the *Xenoceratops* frill, beyond display?
dietpaleontologydinosaurherbivoreXenoceratops