This is a really interesting paper that answers a great question -- do we see bone density and other structural changes in the calcaneus of the DOMEXP wild boar? This is important because we need new and better tools for examining the origins of animal husbandry in the Neolithic. It would also be nice to have more tools for understanding animal husbandry in ANY period. 

As the authors note, previous studies identified morphological differences (via 3d GMM) in the calcaneus, so this seemed like a good element to focus on (although see below). The results are disappointing for those of us interested in applying new techniques to understand the initial development of animal husbandry strategies in the Neolithic. Nevertheless, this is an important contribution and should be published, even if there is a strong bias against "negative data" in academic publishing. 

I do think it would be worthwhile, however, to explore other elements. Other elements, such as the phalanges or distal long bones, would be good to examine. These bones bear more weight than the calcaneus and thus might be more sensitive to locomotion. 

A few small notes:

1) the authors refer to their study as one targeting "microanatomy." I'm not sure cortical density and trabecular bone volume really count as "micro." For bones, I think of Haversian canals or even collagen fibrils when I think "micro."

2) The authors suggest in the discussion that diet might play a role in impacting these factors. Possibly, but certainly not "probably" as the authors say. It's certainly worth following up on (if one were to repeat the DOMEXP experiment), but I suspect there would be little impact from diet except in cases of severe and long-term malnourishment. 

Thank you for the opportunity to review this manuscript. The authors explore the internal anatomy of wild boar calcanea to investigate a potential relationship between internal phenotypic variation and mobility patterns (e.g., of individuals that roam free vs those that are kept in stalls). By doing this, the authors hope to gain further insights into historical domestication processes through the analyses of zooarchaeological specimens. Nonetheless, the authors use both archaeological samples (Mesolithic) and calcanea from modern boar populations, including from the wild and from a genetically-homogeneous population in which different individuals were raised with various mobility restrictions. The calcanea were analyzed using CT-scan data and I found the methodology to be sound and robust. The authors conclude that -inter and probably -intra-population variability is higher than the differences observed between different mobility patterns and therefore, that calcaneal internal anatomy (contrary to external shape, which seems to at least partially work) cannot be used (at least with the variables and methods used) to examine domestication processes unless the populations examined are more or less genetically homogenous (needless to say this is a utopic situation in the archaeological record). Even though the results are not what the authors hoped for (a priori), I find the paper to be highly interesting and an important contribution to zooarchaeologists and zoologists, and thus, worthy of publication. 

I attach a pdf with suggestions and comments, most of which are grammatical corrections or small comments, though various sentences have to be entirely rephrased. However, I want to point out the most important suggestions: 

- The authors mention Table 2 throughout the manuscript but I could not find Table 2. Obviously, this needs to be fixed. 

- I suggest the authors include a table (if this was not detailed in Table 2) with summary statistics (with statistical comparisons if relevant). 

- Fig. 5. could be improved if the convex hull around archaeological samples is not drawn and symbols are made larger. 

- Finally, I urge the authors to be consistent with the terminology used throughout the text (see pdf attached).