The Japanese serow in the Shikoku population has obvious differences from the Japanese serow in the Honshu population, and it seems likely that they are subspecies, but this seems to be a matter of debate.
@PossumRoach
Honshu serows are kept at Morioka Zoological Park, Saitama Children's Zoo, Inokashira Zoo, Kanazawa Zoo, Chausuyama Zoo, Toyama City Family Park, Tateyama Museum, Higashiyama Zoo, Nonhoi Park, and Omachi Mountain Museum.
All other zoos' Japanese serows are Shikoku serows.
However, most zoos that currently have Shikoku serows used to have Honshu serows, so please do not mistake them for Shikoku serows when looking back at past photos!
Comparison between Shikoku serow and Honshu serow↓