The sika deer (Cervus nippon), also known as the Northern spotted deer or the Japanese deer, is a species of deer native to much of East Asia and introduced to other parts of the world. Previously found from northern Vietnam in the south to the Russian Far East in the north, it is an uncommon species that has been extirpated in most areas of its native range, except in Japan, where it is overabundant and present in very large numbers.
Etymology
Its name comes from , the Japanese word for "deer". In Japan, the species is known as the . In Chinese, it is known as .
Taxonomy
The sika deer is a member of the genus Cervus, a group of deer also known as the "true" deer, within the larger deer family, Cervidae. Formerly, sika were grouped together in this genus with nine other diverse species; these animals have since been found to be genetically different, and reclassified elsewhere under different genera. Currently, species in the genus Cervus include the sika, the red deer (of Scotland, Eurasia and Northern Africa; introduced in Argentina and Australia), the wapiti, or elk (of North America, Siberia, Mongolia, and Central Asia).
DNA evidence indicates that the species formerly placed under Cervus are not as closely related as once thought, resulting in the creation of several new genera. The ancestor of all Cervus species probably originated in Central Asia and possibly resembled the sika deer. Members of this genus can crossbreed and produce hybrids in areas where they coexist. This includes sika and wapiti, and introduced sika breeding with native red deer in the Scottish Highlands, a serious threat to the gene pool of the Scottish red deer. However, by comparison, an invasive sika deer in the United States cannot reproduce with a North American white-tailed, mule or black-tailed deer, all of which are placed in a separate genus, Odocoileus.
Subspecies
Serious genetic pollution has occurred in many populations, especially in China, so the status of many subspecies remains unclear. The status of C. n. hortulorum is particularly uncertain and might in fact be of mixed origin, hence it is not listed here.
C. n. aplodontus, northern Honshu
C. n. grassianus, Shanxi, China
C. n. keramae, Kerama Islands of the Ryukyu Islands, Japan
C. n. kopschi, southern China
C. n. mandarinus, northern and northeastern China
C. n. mantchuricus, northeastern China, Korea, and Russian Far East
C. n. nippon, southern Honshu, Shikoku, and Kyushu
C. n. pseudaxis, northern Vietnam
C. n. pulchellus, Tsushima Island
C. n. sichuanicus, western China
C. n. sintikuensis, Taiwan
C. n. soloensis, Southern Philippines (anciently introduced to Jolo island; of unknown subspecies origin, probably extinct) C. n. taiouanus, Taiwan C. n. yakushimae, Yakushima, Japan C. n. yesoensis, Hokkaido, Japan
Description
The sika deer is one of the few deer species that does not lose its spots upon reaching maturity. Spot patterns vary with region. The mainland subspecies have larger and more obvious spots, in contrast to the Taiwanese and Japanese subspecies, whose spots are nearly invisible. Many introduced populations are from Japan, so they also lack significant spots.
The color of the pelage ranges from mahogany to black, and white individuals are also known. During winter, the coat becomes darker and shaggier and the spots less prominent, and a mane forms on the back of the males' necks. They are medium-sized herbivores, though they show notable size variation across their several subspecies and considerable sexual dimorphism, with males invariably much larger than females. They can vary from tall at the shoulder and from in head-and-body length. The tail measures about long.
The largest subspecies is the Manchurian sika deer (C. n. mantchuricus), in which males commonly weigh about and females weigh , with large stags scaling up to , although there had been records of Yezo sika deer bulls weighing up to . On the other end of the size spectrum, in the Japanese sika deer (C. n. nippon), males weigh and females weigh . All sikas are compact and dainty-legged, with short, trim, wedge-shaped heads and a boisterous disposition. When alarmed, they often display a distinctive flared rump, much like the American elk.