Editing Gray whale (section)

===Pacific groups===
The two populations of Pacific gray whales (east and west) are morphologically and phylogenically different. Other than DNA structures, differences in proportions of several body parts and body colors including skeletal features, and length ratios of flippers and baleen plates have been confirmed between Eastern and Western populations, and some claims that the original eastern and western groups could have been much more distinct than previously thought, enough to be counted as subspecies.<ref name=SC65bBRG12 /><ref name=GrayJapan>{{Cite journal|author1=Nakamura G.|author2=Kato H.|title=日本沿岸域に近年（1990–2005 年）出現したコククジラEschrichtius robustus の骨学的特徴，特に頭骨形状から見た北太平洋西部系群と東部系群交流の可能性|url=https://www.jstage.jst.go.jp/article/mammalianscience/54/1/54_73/_article/-char/ja/|journal=哺乳類科学 |volume=54 |issue=1 |year=2014|pages=73–88|publisher=The Mammal Society of Japan, Cetacean Research Laboratory in Marine environmental section in the Graduate School of [[Tokyo University of Marine Science and Technology]], [[J-STAGE]]|format=PDF|access-date=2015-01-16}}</ref> Since the original Asian and Atlantic populations have become extinct, it is difficult to determine the unique features among whales in these stocks.  However, there have been observations of some whales showing distinctive, blackish body colors in recent years.<ref name=Olga2011>Shpak O. (2011). [http://kit.sevin-expedition.ru/news/news_81.html Observation of the gray whale in the Laptev Sea]. Standing expedition of IEE Russian Academy of Sciences.</ref> This corresponds with the DNA analysis of last recorded stranding in China.<ref name=2011insights /> Differences were also observed between Korean and Chinese specimens.<ref name=GrayJapan/>