odocoileus-hemionus

A comparative diagram of deer butts. From Life-histories of Northern Animals: An Account of the Mammals of Manitoba by Ernest Thompson Seton

I. white tailed deer (Odocoileus virginianus)
II. mule deer (Odocoileus hemionus)
III. black tailed deer (Odocoileus hemionus columbianus)
IV. elk (Cervus candanensis)
V. red deer (Cervus elaphus)

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Mule deer (Odocoileus hemionus), in the Painted Desert at dawn. Petrified Forest National Park, Navajo County, Arizona.

Please click either photo for enlarged views.

Bonus etymology: The species name hemionus is a direct transliteration of the Greek ἡμίονος, meaning half (hemi) and ass (onus) - the half-ass deer!