 
      Variation among New & Old World Deer
    The typical deer
        of the Old World is the Red Deer (left); a similar form,
        the Wapiti or American Elk (right) occurs in
        North America. Early explorers recognized that the forms were
        sufficiently similar that both are classified as Cervus
          elaphus, but that there were also clear differences that
        allow them to be recognized as distinct subspecies. Other
        examples included Moose (Alces)
        and Old Word Reindeer vs New World Caribou (both Rangifer
          tarandus). Differences between the continental forms are
        borne out by genetic studies.