The sika deer should be split into four species based on genetics, morphology and voice, although this may be premature based on the presently available evidence. If split, the potential species are "C. yesoensis" from northern and central Japan (Hokkaido and northern and central Honshu), "C. nippon" of southern Japan (southern Honshu, Shikoku, Kyushu, Okinawa, Tsushima and other small islands), "C. hortulorum" of mainland Asia (the Russian Far East, Korea, central and eastern China and northern Vietnam), and "C. taiouanus" of Taiwan.