11. The Stegosaurus Did Not Have Two Brains
There’s a theory that the Stegosaurus had a second brain in its pelvis, but modern theories believe that the cavity in which they previously believe a second brain was, was in fact a storage for a glycogen body – which stored energy. Today’s birds have this structure too, so the Stegosaurus might have indeed have one as well. What we still don’t know is the purpose of their spike, so the main theory is that it was used for mating.