most dinosaurs, and most theropods, had brains no better than present-day reptiles, so far as can be estimated. in a 2001 study of a "carcharodontosaurus saharicus" endocast, hans larsson found that both "c. saharicus" and "allosaurus" had a ratio of cerebrum to brain volume that was very similar to non-avian reptiles. by contrast, the "tyrannosaurus" ratio was slightly in the direction of a more bird-like proportion. since tyrannosaurs are relatively basal coelurosaurs, this is evidence that the coelurosauria mark the beginning of a trend in theropod brain enlargement.