Fauna of endobiotic ciliates of the red deer Cervus elaphus xanthopygus and of the Altai wapiti Cervus
elaphus sibiricus in Asia was studied for the first time. In total, 14 species and five forms of ciliates belonging
to five genera of Ophryoscolecidae and Isotrichidae were found. The species composition of endobiotic
ciliates in all studied individuals of deer appeared to be rather similar. Most of the samples contained Entodinium
wapiti, previously considered specific to the North American wapiti Cervus canadensis. The influence
of different factors on the formation of a certain structure of communities of ciliates, endobionts of the rumen
of the red deer Cervus elaphus, is discussed.