Large-eared deer ( Odocoileus hemionus ) of western North America that lives alone or in small groups at high altitudes in summer and lower altitudes in winter.
Mule deer stand 3–3.5 ft (90–105 cm) and are yellowish brown in summer, grayish brown in winter. The tail is white with a black tip, except on the black-tailed deer ( O. h. columbianus ), a Pacific Northwest subspecies. The male's antlers fork twice above a short tine near the base; a mature male normally has five tines on each antler. It is related to the white-tailed deer .