Reply to Mitteroecker and Fischer: Developmental solutions to the obstetrical dilemma are not Gouldian spandrels

In our study on human pelvic development (1), we propose two hypotheses explaining the narrowing of the female pelvis during postreproductive life. Hypothesis 1 proposes ultimate, evolutionary causes, reflecting selective pressures acting on postreproductive life. Hypothesis 2 proposes proximate, developmental causes, reflecting reduced estrogen levels during postreproductive life. Mitteroecker and Fischer (2) replicate one part of our study—that concerning adult pelvic development—with an independent dataset, taking into account age effects on pelvic shape variation not considered in their earlier study (3). (Note that the smoothing functions used in our study only serve for visual guidance, not for statistical testing.) Rather than testing our hypotheses (1) with new … [↵][1]1To whom correspondence should be addressed. Email: marcia{at}aim.uzh.ch. [1]: #xref-corresp-1-1