4 KudoZ points awarded for this answer. Comment: "Thank you very much for all the contributors and graders. Here, I would pick Dr. Shibasaki's suggestion, "dominant behaviour/subdominant behaviour". Before choosing that, I extensively researched the usage and frequency of proposed phrases. First of all, "rank-order behavior" can be found in the referred site. I think this will be another option for "順位行動" here, but Google showed only 6 examples. I am not always an advocate of Google, but I think the frequency would be a factor in choosing a right word/phrase. It is true that "pecking order" is used in a lot of sites, but, as far as I saw the usage, it is used not only in the field of biology but in other fields such as economics. You will see this situation if you search "pecking order" (with quotation marks) in Google and if you limit that search for Japanese pages only. One of the reason that "pecking order" is frequently used is because it is part of the album title of an CD by Oysterhead ("The Grand Pecking Order"). I also research the usage of "peck order", but I don't think that this will not be the choice. As you see in the following page, this term is specifically translated as "つつき行動", and this reminds that it is the terminology for ornithology, although it is also used in biology in general. http://www.fsinet.or.jp/‾bird/bird/dict/dict_P.html Following the suggestion by Dr. Shibasaki, I presume that "peck order" is strictly used in the field of biology and related fields whereas "pecking order" has earned a more general use for ranking. Anyway, I will pick "dominant/subdominant behavior" (sorry for the "-or" spelling!), but it seems to me that its noun form, "dominance", may replace "dominant". As in the web page of the Primate Research Institute of Kyoto University (京都大学霊長類研究所), "dominance behavior" is assigned a translation like "優位行動", but this "優位行動" itself doesn't have not so many examples (i.e., 7 examples). Here, I presume that the concept of "優位行動" is parallel to that of "順位行動", and I think "dominance behavior" may be used for "順位行動" as well. In the glossary, I enter both "dominant/subdominant behavior" and "dominance behavior". Thanks again. "