Taxonomy
The sika deer is a member of the genus Cervus, a group of deer also known as the "true deer". Formerly, sika were grouped together in this genus with nine other species. Now, only the sika and red deer remain, the latter being divided into three separate species European red deer, central Asian red deer and American elk (though this remains controversial). Recent DNA evidence indicates these deer are not as closely related as previously thought, resulting in the creation of new species and genera. The genera Rucervus, Rusa, and Przewalskium are where most of the former Cervus species now belong. The ancestor of all Cervus species probably originated in central Asia and resembled sika deer. All Cervus species can crossbreed and produce hybrids in areas where they coexist (for example, introduced sika hybridize with native red deer in the Scottish Highlands, where this is a serious threat to the gene pool of the red deer population).
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