Preservation of indigenous gastrointestinal microbiota is critical for successful captive breeding of endangered wild animals, yet its biology is poorly understood. Here, we compared the cecal microbial composition of wild living Japanese rock ptarmigans (Lagopus muta japonica) in different locations of Japanese mountains, and the dominant cecal microbial structure of wild Japanese rock ptarmigans is elucidated. Coriobacteraceae and Lachnospraceae were the two dominant bacterial families in all samples analyzed. At the genus level, 10 genera Olsenella, Actinomyces, Megasphaera, Slackia, Cloacibacillus, Bifidobacterium,Escherichia,Dialister, Megamonas, and Bilophila were dominant. These results reveal the high level of coexistence of lactic acid bacteria (Olsenella and Bifidobacterium) and lactate-utilizing bacteria (Megasphaera). This coexistence should be taken into account for the successful breeding of captive Japanese rock ptarmigans in the national conservation program.