Brief communication: pelvic sexual dimorphism and relative neonatal brain size really are related

Primate species in which the neonatal brain size is large relative to the birth canal tend to have more sexually dimorphic pelves: this is a classic comparative relation, discovered by Schultz and Leutenegger. The original work did not correct for phylogenetic nonindependence of the data points; it only partly corrected for body size; it used ratios in both variables, and the size of the female pubis featured in both x- and y-variables. A recent publication by Tague placed a question mark over the validity of the relation. I therefore retested it, correcting for all four statistical defects. A strongly significant statistical relation exists.