CRAIG K. LORENZ / SCIENCE PHOTO LIBRARY CRAIG K. LORENZ / SCIENCE PHOTO LIBRARY
Rocky Mountain Mule Deer (Odocoileus hemionus hemionus) buck. Named for its mule-like ears, the Mule Deer are believed to have developed during the Pleistocene to the current Holocene period, 10,000 to 12,000 years ago. They are consequently one of the world's most recently evolved mammals. They developed from hybridization of White-tailed Deer and primitive Black-tailed Deer. Rocky Mountain National Park, Colorado.
Model release not required. Property release not required.